The Rosin Bag: Martin Perez

The Rosin Bag is a weekly series that highlights and examines the best and sometimes the worst pitching performances of the week for the Texas Rangers.

In the 2010 Baseball Prospectus, Martin Perez was described by scouts (despite his diminutive frame), as having the ability to project to true stardom. Fast forward to 2013 and most Rangers fans know and understand the difficulties that Perez has had in living up to the hype of his minor league superstar status, but in his last two starts Martin Perez has delivered the type of performance that hints that he has maybe turned that proverbial corner.

Since being called back to the big leagues and starting against the St. Louis Cardinals, Perez is 2-0 and has a 1.32 ERA and has held opponents to a .229 batting average. He has provided two quality starts at a time when this club desperately needed some stability in the rotation because of the injuries and youth this staff has battled all season. Perez has only given up two earned runs in the 13.2 innings since his return from the minors after his so-so outing against the Diamondbacks in May. One of the more intriguing stats from his past two outings, despite the small sample size, was his groundball to fly ball percentages. Against the Cardinals, Perez had nine groundball outs versus 13 fly ball outs compared to almost the complete opposite in his next start against the Reds in which he gave up 14 groundball outs and only seven fly ball outs. Not much to learn from this those numbers other than it’s important to know that Perez has hovered around the 50% groundball ratio since his first year in the minor leagues and is at 48% for this season, which is on par for the norm. What makes it interesting for me is as his strikeout rates decrease compared to his early minor league numbers, will he be able to maintain that groundball percentage which should allow him to be effective long-term at this level? If Perez can hover around the 50% mark he can be a very effective piece in this puzzle in my opinion.

The other question I had after watching his dominating performance against the Reds was what changes has Perez made since that start against the Diamondbacks? It’s always interesting to see what adjustments a pitcher may make during a minor league stint or over time and it’s apparent to me that Perez came back with one slight change in his game plan since that May start. Against the Diamondbacks, Perez threw 95 pitches and 21 of those were sinkers (according to information found at which was his second favorite pitch to the fastball, which he threw 33 times. He threw his changeup 20 times in that game and his slider 14. After returning from the minors in his start against the Cardinals, Perez threw 82 pitches and only 16 were sinkers compared to 28 fastballs and 25 change ups. In his next start on Friday against the Reds, he threw 79 pitches and gave up zero earned runs with 62 of those 79 pitches being fastballs or change ups. A 79% fastball/change combination was very impressive to witness especially considering he was at 65% against the Cardinals in his previous start. This progression in his last two starts getting away from a sinker/curve and relying on his fastball/change combo is intriguing and something to watch in the future. What is also surprising is his diminished use of his curveball, which like I said previously is what scouts raved about during his time in the minors as a young prospect. He has thrown his curve three times each in the last two games and his slider only 17 times.

These are not things that should be concerning but rather an interesting thing to look at as we watch Martin Perez adjust and try to prove that he is capable of being a consistent member of the rotation for this year and hopefully years to come. How Perez uses his curveball and slider in his next start(s) is something I will definitely be keeping my eye on and I’m sure opposing scouts will as well. 

Jeff  Johnson is a Staff Writer for ShutDownInning. He can be reached at or on Twitter @Houstonhog
Jeff Johnson

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