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« Dr. Mike Marshall Training: Javelins and Bucket Lids | Main | Texas Rangers Prospects: Wilmer Font and Evan Reed »
Wednesday
May132009

Texas Rangers Prospects: Martin Perez and Juan Grullon

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.

Martin Perez's pronation curve frame-by-frame.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.

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