Spring, TX - a suburb of Houston - has produced quite a number of early-round draft picks over the past several years. It looks like Klein's Matthew Purke will join a list that includes former Klein players Josh Barfield, Chris George, and David Murphy, as well as Josh Beckett, Sam Demel, and Daryl Jones from Spring High School.

Purke stands at 6-foot-3 and weighs 180 pounds. Scouts like his projectability and believe he could add velocity as he gets stronger. He already sits at 92-94 MPH, occasionally throwing a tick or two harder. His primary off-speed pitch is a slurve-type offering called a slider by Baseball America and a curve by the Major League Scouting Bureau. Whatever you call it, it's one of the best breaking balls in this year's high school draft class.

Conflicting reports from the same two sources have his change up somewhere between "unknown" and "good."

Purke is believed to have a strong commitment to Texas Christian University in Fort Worth, so signability has become a concern for some clubs. Rumors of his signing bonus demands have ranged from $2 million to $7 million, but the most recent rumors have him in the neighborhood of $3 million.

Almost every report on Purke has mentioned something about questionable mechanics. Typically, high school deliveries are full of flaws and quirks, but rarely do these scouting reports go out of their way to mention them.

Baseball America mentions Purke's slinging action, saying that it is neither violent nor smooth. I guess that would be... Average? Typical? Expected? Outside of this specific mentioning of a flaw, I could only find generic references to his mechanics. I wanted to have a look for myself.

I located a solid video on YouTube, looked at it, and made some still photos. Here's the video, courtesy of Baseball Factory: [video has been made private and can no longer be embedded]

There are two big things that jump out at me, but first, I want to say that outside of his arm action, there really isn't much to complain about. He steps nearly straight forward, landing only a few inches closed.

Purke stays closed very well and gets great hip rotation and shoulder rotation. He even stands relatively tall through his release. His core does its job very well.

If I had to pick one part of his body action to complain about, it would have to be his somewhat stiff front leg. That might be the source of the reported inability to repeat his delivery consistently.

The still shots below were taken from the same pitch, the first one in the video.

Now, here are the flaws in his arm action as I see them. In the first frame, you can see that Purke's entire pitching arm has been moved about as far toward third base as possible. Skipping ahead to the final frame, you get an idea of how much horizontal acceleration takes place. When his arm finally starts moving forward, the centripetal force from the curved path results in forearm flyout. The Baseball America "slinging" comment is dead-on.

Pronated releases can help protect against the negative effects of forearm flyout, but there aren't enough frames available to be able to determine if, or to what extent, Purke pronates into his release.

The second frame shows a massive scapular load at foot plant. This puts extra stress on the anterior capsule of the shoulder, and the extra movement of the head of the humerus places the glenoid labrum at risk.

Still in the second frame, his forearm is past horizontal, avoiding an inverted arm position, but his forearm is almost 180° of external rotation from the throwing position shown in frame three. This causes a late forearm turnover.

Because his elbow is flexed to near 90° during his late forearm turnover, he experiences a pretty intense reverse forearm bounce which puts his ulnar collateral ligament at risk.

Here's an overly simplistic look at his follow-through. The first frame shows where his arm winds up after primary deceleration. His arm continues in the curved path and winds up finishing hard toward third base. There is no recoil evident at this frame rate, and his arm winds up tucked in softly at his waist.

There could be some extra stuff going on in his shoulder, but the standard 30 frames per second video does not reveal it.

So... what are you saying?

Overall, Purke's mechanics could be a lot worse. That said, I'm not a fan of his arm action at all. The slinging action reported by Baseball America is clearly present, and he puts a lot of torque on his elbow. Long term, he has almost no chance to stay healthy with these mechanics.

Any team that drafts Purke will have to ask themselves which risk they want to take: leave his mechanics alone and risk his arm falling apart - or - change his mechanics and risk his stuff dropping off.

Robbie Ross. LHP, 5' 11", 185 lbs, Born: June 24, 1989. The 2008 2nd round pick of the Texas Rangers was said to have 1st round talent. Some minor signability concerns allowed Ross to slip into the early 2nd round where the Rangers selected him and eventually signed him for a reported $1.575 million signing bonus. He has yet to make his professional debut, but Ross could be in line to join the Spokane rotation in less than a month.

In a post-draft interview with Ross, Jason Cole of Scout's LoneStarDugout.com wrote the following:

Ross enters pro ball with an advanced changeup to go along with his fastball and slider. The southpaw’s fastball, as he explains in the interview, generally sits in the upper-80s, low-90s, but he has shown the ability to dial it up to 94 mph at times.

Out of the wind-up, Ross has a very high leg kick, reminiscent of Nolan Ryan's leg kick. After the kick, he starts to drift forward before sitting down on his back leg. This loads the leg very well, but it also lowers his potential release point. From lower release points, pitches take more flattened paths to the plate compared to pitches thrown from higher release points.

Ross keeps his front leg and hip closed until right before foot plant. When he lands, his center of mass almost completely stops moving forward. The momentum from his drive helps him open his hips really well and pulls his back foot forward off the rubber. I prefer this action to the foot drag seen in a lot of pitchers. (In Ross's 2008 MLB Draft Report, he is seen dragging his back leg like dead weight on his first pitch and last pitch, both presumably change ups. I did not identify any change ups within my video sample.)

Worth mentioning is the path his front foot takes toward his landing. His front leg moves in a sweeping motion. By the time his front foot plants, it is moving more toward third base than it is toward the plate. This gives him a soft landing and sort of kick-starts his hip turn as he turns his front leg to face the plate. I like the soft landing but prefer a more direct stride.

As one would expect, Ross's hip rotation leads to strong shoulder rotation. Ross maintains extremely level shoulders throughout. Because he keeps his shoulders level, his elbow moves in a sharp arc around his body. Ross picks up the ball mostly with his shoulder, but he reverse-rotates his shoulders and takes his elbow well behind his back and toward third base. All of this creates a curved path to release, resulting in the centripetal force that causes forearm flyout.

Ross's pronation seems to occur during release. This provides a degree of protection from the negative effects of forearm flyout, but at this frame rate and camera angle, it is impossible to determine whether it prevents his ulna from slamming into his humerus. I was unable to identify any sliders in my sample, so I do not know if he supinates his release for that pitch.

At foot plant, Ross's arm is nearly vertical, but active external rotation is still taking place. This creates a reverse forearm bounce where the baseball is moving toward third base and his elbow is moving toward first base. This indicates a large valgus torque in his elbow and is a risk factor for his ulnar collateral ligament.

Ross's follow-through is where things get interesting. The continuation of the centripetal force described above causes his arm to wrap slightly across his body. There is some recoil, so I have some concern for the posterior capsule of his shoulder, mainly the infraspinatus and teres minor muscle tendons.

Finally, Ross has a weird little hop-twist after everything slows down. This is probably caused by a continuation of his powerful shoulder rotation. He ends in an athletic yet awkward looking stance.

Joseph Ortiz. LHP, 5' 7", 175 lbs, Born: August 13, 1990. When Ortiz debuted with the Low A Clinton Lumberkings last season, he was only 17 years old. Definitely one of the smaller players in the league, Ortiz pitches beyond his stature. Even as one of the youngest players in the league, Ortiz's only statistical fault was a high walk rate - 4.5 per 9 innings. He struck out just over 7 batters per 9 innings and allowed just under 6.5 hits per 9 innings.

This winter, Cole compared Ortiz to former Rule V pick Fabio Castro because of their similar body types and repertoires. From Cole's scouting report:

The lefty constantly attacked hitters with his 87-91 mph fastball... hard, late-breaking slider... [and] a promising, occasionally used changeup...

Ortiz has a very compact delivery without a lot of flair or wasted movement. His stride is fairly standard, and he lands noticeably closed. His front leg sweeps like Ross, but Ortiz puts his foot down before it sweeps all the way across.

Ortiz pulls his elbow down and to the side as he flexes his trunk forward. This can help raise the release point but prevents a few trunk muscles from adding to the pitch and puts a little extra stress on his spine.

His hip rotation isn't great, and he drags his toe in the dirt pretty firmly. Ortiz flexes his trunk over his front hip, so hip rotation - or lack thereof - isn't a huge factor for him. This drives his throwing shoulder in a nearly straight line toward home plate.

Ortiz takes the ball only slightly behind his back, but noticeably drives his elbow toward first base before as he explodes toward release. This lateral movement causes forearm flyout, but Ortiz, unlike Ross, pronates late, making him more susceptible to its negative effects.

Despite his compact delivery, Ortiz has a late forearm turnover. This leads to active external rotation at his shoulder after foot-plant and creates a reverse forearm bounce where, like Ross, the ball and his elbow are moving in opposite directions.

Ortiz's arm also wraps slightly across his body, but with a more alarming recoil. Ortiz's arm appears to collide with his rib cage after the throw. The collision doesn't appear to be terribly violent, but the leverage caused by the impact can place extra stress on the posterior capsule of the shoulder where the muscles are already contracting to help decelerate the arm.

At the very end, Ortiz actually does have a little flair. Instead of a hop-twist, Ortiz's post follow-through action resembles the finish of Dr. Mike Marshall's pitchers. His shoulders and arm point at the target while his lower half turns toward second base.

This doesn't mean much for his pitches or for his health, but it's notable because it puts him in a horrible fielding position. I imagine that you'd see a lot of bunts against him in close games.

Joseph Wieland. RHP, 6' 3", 175 lbs, Born: January 21, 1990. Normally, when you talk about a skinny high school pitcher with an 88-91 mph fastball, you expect a certain amount of projection. A scout for the Major League Scouting Bureau said, "There isn't much to project; he's not going to be a very physical guy." I'm definitely not a fan of the overly generic and often hedged Scouting Bureau draft reports, but this comment left me confused.

After being drafted by the Texas Rangers in the 4th round of the 2008 MLB First-Year Player Draft, Wieland had a very strong debut with the Arizona Rookie League Rangers. By the time fall instructionals arrived, Wieland's fastball was consistently 90-93 mph - a modest but solid 2 mph gain in only 4 months. There may or may not be more where that came from, but there's definitely room for projection.

The scout also pegged Wieland as an above average strike thrower, and that certainly has been the case so far in his professional career. In his 43.2 innings in 2008, Wieland averaged a meager 1.65 walks per 9 innings. What was really impressive was the rate at which he missed bats. In those same 43.2 innings, Wieland allowed only 32 hits while striking out 41.

Wieland recently made his 2009 debut with low A Hickory. The following video was shot during spring training.

Wieland has an easy, powerful stride. He lands fairly closed, but twists his landing leg to point his toe directly at the plate. There is some awkwardness when his back leg comes off the rubber. Because he lands closed, Wieland's back hip and leg are driving "through" his front hip. This is an example of a stride cutting off hip rotation.

Interestingly, his hip rotation doesn't seem to affect his shoulders. He gets good forward flexion, and his shoulders rotate as a single unit rather than separately.

Good shoulder rotation usually leads to a controlled follow-through, but Wieland's arm flies across his chest. This tends to stress the posterior capsule of the shoulder, particularly the supraspinatus and infraspinatus muscles of the rotator cuff.

Wieland flexes his wrist toward 1B.Wieland takes his elbow pretty far toward first base, and even flexes his wrist in that direction. Though some people don't like this type of wrist flexion, I tend to view it as more of a quirk than anything else. The movement toward first base leads to forearm flyout when he drives his elbow back to the third-base side to throw the baseball.

When Wieland's front foot lands, his pitching forearm is nearly vertical, and active external rotation has already stopped. Though he picks up the ball with his elbow, he avoids an inverted arm position.

A reverse forearm bounce is present, but since the ball and his elbow aren't travelling in oppposite directions, it is fairly small.

Wieland appears to pronate pretty well on both his fastball and his curveball and very well on his change up.

Matt Thompson. RHP, 6' 3", 210 lbs, Born: February 10, 1990. A 7th round pick in last year's draft, Thompson recieved a signing bonus worthy of a 2nd round pick. He impressed the Rangers in a pre-draft workout at Rangers Ballpark with a fastball that flashes into the mid-90s and a sharp curve in the 74-77 mph range.

Thompson is a local product from Burleson, TX and attended Grace Preparatory Academy in Arlington, TX - practically in the Rangers' backyard.

He had an awful debut statistically. In only 8.1 innings, Thompson allowed a staggering 25 hits. He walked 4 hitters as well but struck out 12 to maintain a 3:1 K:BB ratio.

Thompson was really impressive at spring training, but he might not make his 2009 debut until Spokane takes the field in June.

Thompson has a high leg kick, gathers himself without drifting, and then goes into sort of a modified drop-and-drive stride. He lands just a bit closed - somewhere between my offset camera position and the plate - and keeps his shoulders closed extremely well.

Thompson flexes his trunk and rotates his shoulders simultaneously, and he does so while staying fairly tall. This description is similar to what I said about Neftali Feliz's trunk and shoulders, and even though Thompson does this very well, Feliz does it much better.

He limits but does not eliminate lateral movement of the baseball - both toward first base and toward third base - and tilts his shoulders to raise his elbow. These actions can help prevent forearm flyout and allow Thompson to use his triceps to apply force to the baseball.

At foot plant, Thompson's forearm is barely above horizontal, so he is still engaged in active external rotation. Because he is still actively externally rotating his pitching arm the baseball is moving toward first base when his elbow starts moving toward third base. This is a more extreme example of reverse forearm bounce, when the elbow and baseball move in opposite directions.

Thompson does not actively pronate on either his fastball or his curveball. On a more positive note, there is no evidence of supinated releases either. I wasn't able to identify any change ups from the pitches I captured.

Martin Perez. LHP, 6' 0", 165 lbs, Born: April 4, 1991. Venezuelan Martin Perez has been the left-handed pitching prize of the 2007 Latin American free agent class. The Texas Rangers won the bidding for Perez and held him back until they unleashed him on the Northwest League in 2008 against players that were typically 3-4 years older than the then 17-year-old Perez.

Walks were a small problem for Perez, and he was hit at a .274 clip, which isn't bad but isn't anything to brag about either. This resulted in a 3.65 ERA and a rather large 1.52 WHIP. His strikeout rate was very good.

He threw only 61.2 innings in 2008, so I don't expect him to jump past 100 this season. That said, he's already surpassed 25 innings in 2009. In that short sample, still against players much older than he is, Perez has lowered his walk rate (from 4.1 per 9 innings to 3.0), dramatically lowered his hit rate (from 9.6 per 9 innings to 5.7), and improved his already solid strikeout rate (from 7.7 per 9 innings to 10.5).

Still only 18 years old, Perez has some serious projection left.

You can see in the video several things that I mention quite often when talking about pitching mechanics. He strides slightly closed, drags his back foot, and has a little bit of a reverse forearm bounce. Perez picks up the ball well, but doesn't supinate as part of his pick-up. As a result, he doesn't rely on forceful external rotation to put his arm into throwing position, but he still has a late forearm turnover.

Perez has a very large back bend, similar to that of Tim Lincecum and Derek Holland, from which he drives his shoulder directly over his landing hip. This gives him a straight-line shoulder drive, but I am not a huge fan of the way Perez pulls his trunk down into his front leg.

This pull-down is a tenet of Jaeger Sports' long-toss program, and it can lead to good arm actions, but I worry about the stress it might place on the landing hip and spine. Of course, Perez didn't spend time with Jaeger Sports, he's from Venezuela, but the point still stands.

This pull-down leads to Perez's fairly uncontrolled follow-through. His initial finish is high, but he still has a violent-looking wrap across his body. This type of follow-through tends to stress the posterior capsule of the shoulder and can lead to rotator cuff issues, specifically in the infraspinatus and supraspinatus muscles.

Dr. Mike Marshall advocates throwing breaking pitches with pronation instead of with the more traditional supination. This works well in his pitching motion and for his pitchers, but some critics have suggested that throwing these pitches is difficult or impossible for pitchers with more traditional mechanics.

I hereby offer Martin Perez as an example of a pitcher with traditional mechanics rather easily throwing a pronation curveball. Take special notice of his palm as he approaches release and immediately after release. Perez's palm clearly turns from inward, to forward at release, and to outward during follow-through. [Click the image to enlarge.]

Perez pronates like this on each of his pitches - fastball, curveball, and change up - and it is excellent for both health and performance. Pronation allows for better ball rotation (more spin therefore more movement) and helps protect the elbow from forearm flyout. This is a good thing because Perez doesn't get his arm nearly as vertical when he throws his fastball and change up compared to when he throws his curveball.

Juan Grullon. LHP, 6' 0", 185 lbs, Born: March 4, 1990. I dug around for information on this guy, and there simply isn't much to be had outside of his 2008 Dominican Summer League statistics which are pretty exciting.

The Dominican lefty threw 48.0 innings and allowed only 37 hits while striking out 67 and walking 25, a few too many. Grullon did not allow a homerun. His efforts were good for a 6-1 record and a 2.44 ERA.

We could see Grullon stateside this year with either Spokane or the AZL Rangers. He will be 19 years old all year.

Grullon is extremely compact. He doesn't doing anything flashy, and it almost looks like he's not trying.

His front leg is actually pretty active through his stride. Grullon seems to almost kick into his landing. This action applies force in the direction opposite to the pitch, but it also gives Grullon leverage to rotate his hips.

Grullon picks up the baseball in almost exactly the same manner as Martin Perez (above). He essentially uses a pendulum swing motion but lacks the supination action. As with Perez, this reduces the required external rotation torque required to lay his forearm back but still leads to a late forearm turnover. The important part is that the resulting reverse forearm bounce is very minor compared to most other pitchers with traditional mechanics.

As Grullon opens his shoulders to throw the pitch, his glove arm just sort of hangs there. He maintains a firm front side, but he could be using this arm to actively contribute to more powerful shoulder rotation. The lazy glove arm makes it look like Grullon is using a pull-down like Perez, but Grullon stays taller through his delivery.

Grullon has some forearm flyout as well, but it is hard to determine to what extent he pronates his pitches. The evidence is less convincing than in the Perez video. Having looked at my raw footage of Grullon, it looks like he definitely pronates on a few of his pitches, but for the most part, he does not pronate. I found no evidence of supinated releases.

The simplicity of his motion allows Grullon supreme control over his follow-through. Under such control, Grullon's pitching arm stays on the pitching arm side of his torso; it does not wrap across his body. His pitching arm is decelerated so well by his latissimus dorsi that his elbow actually winds up tucked in next to his rib cage as he finishes his follow-through.

Wilmer Font. RHP, 6' 4", 210 lbs, Born: May 24, 1990. The Texas Rangers signed man-child Wilmer Font out of Venezuela during the 2006 international signing season only a couple of months after he turned 16. Font is an extremely raw talent still, but parts of his game are starting to show signs of polish.

Font can run his fastball into the upper 90s, and he has shown very promising off-speed pitches in his change up and curveball. The part he has struggled with to this point has been control. In just over 65 innings of stateside work, Font has allowed only 53 hits while striking out 82, but he has also allowed 35 walks. That's not all. More than 20 batters, possibly 30 or more, have reached base via hit-by-pitch against Font. (Does anyone know the actual HBP numbers? I couldn't find them.)

There's no questioning his stuff, though. Still not quite 19 years old, Font has plenty of time to work on refining his it. Those signs of polish I spoke of? Over Font's last two appearances (both of them starts, with limited pitch counts) spanning 8.2 innings, Font allowed only 6 hits and 2 walks while striking out 8, hitting 0 batters, and throwing only 1 wild pitch.

This 210 fps video is from a March 19, 2009 spring training appearance in a Low A game.

The first two things I noticed were the large reverse rotation of his shoulders and how far he takes the ball toward first base. In this video, you can very easily see what pitch Font is about to throw. At full speed, I know this is harder to see, but his change up still has to be a dead give away.

Font's stride is slightly closed, and his back leg appears to be driving across his landing leg pretty powerfully. In the video, it almost looks like the front of his back leg is driving into the side of his landing leg. Pitchers typically put a lot of torque on their landing hips, but Font seems to be pushing the limit. I have no way to measure it or even estimate it, but I know it looks bad.

His front foot lands slightly open despite his closed front hip. Font had a knee injury last season. This little quirk could either be the result or the cause of that injury.

He pulls his front shoulder a little bit before driving his pitching shoulder forward, but the timing is still pretty good as evidenced by his mid-to-upper-90s fastball.

Because of his massive reverse shoulder rotation, Font has to drive his pitching shoulder a long way toward third base before it really starts moving toward the plate. As a result, his elbow and hand have even longer paths to travel. The short of it is that Font has extreme forearm flyout, and since his release is in a low-3/4 arm slot, his ulna's olecranon process is at the mercy of his eccentrically contracting brachialis.

At 210 frames per second, Font's hand is still moving too fast for me to conclusively say whether he does or does not pronate through his release, but it looks like he does not pronate on any of his pitches.

I like his follow-through a lot. It is similar to that of Neftali Feliz (featured previously) and that of Evan Reed (below). Thanks to strong shoulder rotation, Font avoids wrapping his arm across his trunk. His primary deceleration is handled chiefly by his latissimus dorsi, and afterward, very little deceleration is required to bring the arm to a complete stop.

Evan Reed. RHP, 6' 4", 225 lbs, Born: December 31, 1985. Drafted out of Cal Poly by the Texas Rangers in the third round of the 2007 MLB First-Year Player Draft, Evan Reed had been a closer, but he was promptly pushed into the short-season Spokane rotation after a quick start. Reed earned a promotion to Low A Clinton after only 7 appearances. His strikeout rate dropped from 11.7 per 9 innings to only 5.0 per 9 innings, but his results improved everywhere else.

2008 saw Reed struggle in the High A Bakersfield rotation. He has special stuff, but he struggles to control it. His fastball is typically a 92-95 mph pitch that often looks like it's moving faster when it gets to the plate than when it left his hand - amazing life. Reed's off-speed pitches have looked like pitches with plus potential at times, but more often than not, he has struggled to harness the two.

Walks and deep counts hurt Reed's pitch counts and his ERA, so the Rangers moved him back to the bullpen for 2009 - for now, at least. Still only 23, Reed has the stuff to make up ground and jump back into a rotation, but he needs to find a way not only to control his stuff but to command it as well.

Reed has a very powerful looking stride, but if you pause the video at foot plant, you can see that his power is directed at the [off-center] camera instead of the plate. This is inefficient but pretty common. A closed landing like this can cut off hip rotation, but Reed pulls himself forward and is able to open his hips almost directly toward the plate before he releases the ball. Try pausing the video at pitch release, and then look at his hips.

Thanks to his excellent hip rotation, Reed is able to get excellent shoulder rotation as well. Part of his excellent shoulder rotation is due to the way he flexes his trunk across his driveline. Because he strides closed, he has to drive across that stride line to get the ball to the plate. This is more inefficient than it is injurious, but it can add stress to the landing hip and lower back.

His pick-up is a little better than average, but it isn't particularly close to the pendulum swing that I like. Reed pushes down, straightening his pitching arm, and away, but instead of continuing the swinging action, he picks the ball straight up with some active external rotation.

Reed's arm is up and ready by the time his shoulders start to rotate, but the external rotation from his pick-up creates some layback inertia that is amplified by his rotating shoulders. This results in a reverse forearm bounce where the ball is moving toward first base while Reed's elbow is moving toward third base.

From that point forward, Reed's mechanics look to be well above average. His shoulder tilt helps him pick up his arm into a more vertical position to help reduce the effects of forearm flyout, and he seems to pronate through the release of every pitch in this video. Reed's follow-through is very good thanks to his excellent shoulder rotation. His arm wraps across his torso rather gently after his back and rotator cuff have taken care of primary deceleration.

Reed also bears an uncanny resemblence to fellow Texas Rangers RHP prospect Thomas Diamond.