Brandon McCarthy. RHP, 6' 7", 200 lbs, Born: July 7, 1983. Okay, he's not a prospect, but I'm not renaming my series because of one guy.
Since coming to the Texas Rangers, McCarthy has struggled with two things: health and command. It's a little early to declare either of those as "overcome," but so far this season he looks healthy and strong.
McCarthy's fastball has generally been an 89-92 mph offering which, by itself, is nothing special. Two other elements make it a pretty special pitch, though. His high release point gives his pitches a great downward plane to the strike zone, and he gets excellent "rising" action from a crazy amount of backspin. The combination of these two gives his fastball a unique look for the batter.
For someone with a soft landing on a flexed front leg, McCarthy gets very little power from his legs. In this case, when his front foot lands, his legs stop contributing to forward movement and the following hip rotation is purely inertial. His trailing hip even drags his back foot like an anchor.
McCarthy has a tendency to drag his arm behind his body when he throws his fastball. Arm drag occurs when the pitcher's body gets too far ahead of the arm. In other words, the arm lags behind the body. This is mostly a timing issue, but it can lead to health problems in the shoulder. Performance-wise, arm drag tends to lead to poor command and a preponderance of pitches that are high, outside, or both.
In this video, his front shoulder opens a little early, but he keeps his pitching arm from lagging behind.
When McCarthy pulls his front shoulder, he's using a large number of his trunk muscles. To drive his pitching shoulder forward, he uses the rest of his trunk muscles. By breaking his shoulder rotation into two separate actions, McCarthy's trunk muscles do not work in concert. The result for McCarthy is slower, less powerful shoulder rotation with a large degree of forward flexion in his trunk.
For an example of someone who uses his trunk insanely well, Neftali Feliz has both a powerful shoulder rotation and a large degree of forward flexion (see Texas Rangers Prospects: Neftali Feliz and Tae Kyung Ahn for more details). Notice that Feliz's shoulders rotate together as a single unit, not separately. Also notice that he stays fairly tall, while McCarthy sort of bends in half at the waist.
Rangers blogger Mike Hindman suggested that McCarthy has an inverted W. McCarthy's arms, though, are well past the inverted W shape when his front shoulder starts to open up. He still has a late forearm turnover and a reverse forearm bounce.
It's hard to tell from this angle, but McCarthy's reverse forearm bounce might be exaggerated by some elbow flexion. By this, I mean that he picks his elbow up high enough that gravity plus natural elbow flexion - rather than inertia - appear to be causing some of the ball's downward motion. This view is inconclusive, but I don't believe his ulnar collateral ligament would hold up for very long if inertia alone caused a bounce that large.
As McCarthy drives into his release, he lifts his elbow just above the line across the top of his shoulders. At release, his humerus usually approaches vertical. This prevents forearm flyout - even though he takes the baseball toward first base during his pick-up - and allows McCarthy to powerfully contract his triceps brachii.
McCarthy pronates into his release on each of his pitches, and if you look closely, you can see his elbow pop-up early in the follow-through. This is fairly similar to the pop-up in Dr. Marshall's arm action that he has demonstrated to be a result of using the latissimus dorsi to both extend and internally rotate the upper arm (see Dr. Mike Marshall on MLB Network).
His follow-through is not spectacular but is fairly standard for traditional pitching mechanics. One negative aspect is that he falls so dramatically toward first base after every pitch. (When he pulls his front shoulder, he's also moving his center of mass in the same direction which causes a balance shift.)
In summary, I think McCarthy could get much better results from his legs and core, but I like his arm action. If he can have success with these mechanics and stay healthy, though, there's no reason to change them.
Ezequiel Rijo. RHP, 6' 4", 190 lbs, Born: September 12, 1990. Rijo pitched in the Dominican Summer League in 2008 and posted some interesting numbers including 48 hits (only 2 homeruns) and 41 strikeouts in 71.0 IP. I don't recall anything about his stuff, though his numbers suggest a fastball with decent movement but not overpowering velocity. In the video, you can see three pitches being thrown: a fastball, a change up, and a slider that you have to look closely to see.
I went pretty long on McCarthy, so I'll keep Rijo's report nice and short. Let's take a look at the video.
Rijo's leg drive is shockingly similar to McCarthy's, but Rijo's looks more intense and appears to lead to better hip rotation.
Interestingly, Rijo also pulls his front shoulder before driving his pitching shoulder. Rijo's glove arm is only slightly more aggressive than McCarthy's glove arm, and his result is the same as McCarthy's - poor shoulder rotation with extreme forward flexion of the trunk.
Rijo has a very sound ball pick-up. We can't see his whole pick-up, but we do know that he doesn't take the ball behind his back and that his elbow doesn't reach shoulder height before the ball. Unfortunately, he still has a late forearm turnover and a large reverse forearm bounce.
Forearm flyout is another potential issue for Rijo since his arm isn't really close to vertical except for his change up. His pick-up helps limit his forearm flyout risk. Because he never takes the ball laterally toward first base, his lateral acceleration of the ball toward third base is very minor.
His follow-through is fairly average, and he gets himself almost immediately into an excellent fielding position.