Newly-Extended Perez Must Improve Breaking Stuff to Take Next Step

The Texas Rangers have locked up yet another young left-handed starter, signing Martin Perez to a four-year, $12.5 million extension with three club options that could extend Perez's stay in the Lone Star State to 2020 and pad his pockets to the tune of $32.5 million.

A perennial top prospect, Perez erased memories of his rough big league stint in 2012 by posting a park-and-league-adjusted ERA that was 14 percent above average (114 ERA+). The 22-year-old enjoyed arguably the best rookie season ever for a Texas lefty, as only Mike Mason (114 ERA+ in 1984) matched him while throwing 120+ innings. Perez displayed sharp control (2.7 walks per nine innings) and racked up ground balls (47.9 percent of pitches put in play), both of which bode well for his future. But he also punched out just 6.1 batters per nine frames, far below the 7.2 average for starting pitchers in this strikeout-saturated era. To get more swings and misses, Perez will have to improve his pitch location with his breaking stuff.

Perez already has an out pitch in his changeup, which generated far more whiffs (39.7% of the time batters swing) than the league average (29.4%) and limited hard contact (.307 opponent slugging percentage, 90 points below the MLB average). His curveball and slider, on the other hand, induced swings and misses just 19% of the time (29.9% average for breaking pitches) and were frequently laced into the gaps (.437 slugging percentage, 92 points above the MLB average).

Why did hitters square up Perez's breaking pitches? The young lefty struggled to command his slider and curve, too often leaving breaking balls over the heart of the plate:

Perez's pitch location with his slider and curveball, 2013

Perez threw 29% of his sliders and curves to the vertical middle of the strike zone, third-highest among lefty starting pitchers in 2013. Belt-high breaking stuff tends to get clobbered, with hitters swinging through just 12.9% of sliders and curves thrown over the middle of the plate and slugging a collective .461. Perez was no exception, getting whiffs 13.8% of the time and allowing a .556 slugging percentage when tossing a belt-high breaking pitch.

The recent history of low-strikeout lefties who nonetheless posted quality ERAs during their rookie season is mixed. On the wildly positive side, Andy Pettitte pitched into his forties and cobbled together a career that may get him some Cooperstown consideration. However, the list of low-K lefties (six or fewer strikeouts per nine) with an ERA similiar to Perez (10-20 percent better than the league average) also includes the likes of Gustavo Chacin, John Lannan and John Halama. To be more like Pettitte and less like Halama, Perez needs to complement his knockout changeup with better-located breaking pitches.

Martin Perez's Changeup a Plus Pitch

Martin Perez has stepped forward as a crucial part of the Texas Rangers' starting rotation, providing quality outings with Matt Harrison (back surgery) out for the season. The 22-year-old lefty has done a pretty convincing Harrison impression thus far, making up for a modest strikeout rate (6.2 per nine innings) with few walks (2.6 BB/9) and plenty of ground balls (49 percent of pitches put in play). Perez's park-and-league adjusted ERA is 22 percent above average this season (122 ERA+), besting all American League rookie starters throwing at least 75 frames, save for Tampa Bay's Chris Archer.

Perez is thriving thanks to his changeup, which he has tossed 24 percent of the time. Opponents are slugging a paltry .287 when he pulls the string, putting Perez's change just outside the top 10 among starters and ahead of changeup aficionados like Matt Cain (.291), David Price (.313) and James Shields (.315).

What makes Perez's changeup so nasty? Here's more on Perez's plus pitch as he prepares to take on Chris Sale and the Chicago White Sox.

• Perez buries his changeup at hitters' knees, locating nearly two-thirds (65 percent) of them down in the strike zone. The MLB average, for comparison's sake, is about 56 percent. Keeping his changeup low, Perez has induced a ground ball 60 percent of the time that hitters put the ball in play (51 percent MLB average).

Perez's changeup location

• He's getting hitters to chase his changeup off the plate about 42 percent of the time, compared to the 36 percent MLB average. Batters are a combined 3-for-26 (.115) when they chase Perez's change out of the strike zone.
• The lefty uses his changeup in any situation, throwing the pitch with nearly the same frequency whether he's behind the hitter (22 percent), even (23 percent) or ahead in the count as (27 percent).
• Perez's changeup is unusually hard, with an average velocity (84.7 MPH) well above the league average for lefties (81.9 MPH). The only southpaws who throw a speedier changeup are Francisco Liriano (86.3 MPH average), Jon Lester and Jose Quintana (85.3 MPH).

Martin Perez's Changeup: The Real Deal?

Tuesday night, Texas Rangers starter Martin Perez tossed six innings against the Orioles holding them to two earned runs on six hits, four strikeouts and one walk. Since his 2013 debut on May 27, he's made five starts and the victory moved him to 3-1 this season. His ERA now sits at an impressive 2.08, the lowest among American League southpaws.

2013 is not 2012

After four years in the Rangers' farm system as a starter, the organization wasn't sure what the future held for the still just 22-year old Perez. Last season, he struggled over six starts with the big club posting a 5.88 ERA  and 1.73 WHIP .

But something changed for him pitching for Round Rock Triple A to start this season posting a 1.75 ERA and a 1.028 WHIP.

Rangers third-baseman Adrian Beltre told ESPN Dallas' Jeff Seidel that Perez is "a different guy" than they saw last season, and that he is "attacking the strike zone" much more. Increasing his strike zone percentage from 47.7 percent last season to 51.4 percent thus far in 2013, Beltre is absolutely correct.

More than any other pitch, the difference is Perez's changeup.

Perez changeup frequency over last two seasons vs. righties

As you can see, last season Perez had trouble finding consistency commanding his changeup against right-handed hitters. This season, his command of the pitch has improved noticeably, pinpointing the low-and-outside corner of the zone with consistency.

Take a look at the difference

Because Perez has proved capable of locating the pitch so consistently, opponents have become more willing to expand the zone and chase his changeups outside of the strike zone.

Last season, that wasn't the case. He threw fewer changeups in the strike zone and batters were less inclined to swing at changeups located out of the zone.

Opponents' swing rate on Perez's changeup located out of the strikezone

Because Perez struggled to command his changeup last season, right-handed hitters offered at only 24.6 percent of those located out of the zone. This season, that swing rate has increased dramatically to 42.2 percent and has directly impacted right-handed batters' success against the pitch. 

	2012	2013
Zone%	37.3%	49.4%
Chase%	24.6%	42.2%
SLG	.360	.290
BABIP	.333	.182
WHAV	.160	.097

Since his May 27th debut: 

• Perez is throwing more changeups for strikes and generating more frequent swings on out-of-the-zone changeups. Consequently, right-handed hitters have not enjoyed the same amount of success this season as they did in 2012.
• Perez's .182 BABIP on changeups ranks as the second-lowest among left-handers.
• His .097 WHAV and .290 opponent slugging percentage are enough for 11th-best against right-handers.  

What does this all mean?

Because of that changeup, Perez is quickly becoming one of the best young left-handed starters in baseball. His refined command of the pitch within the zone has held right-handed batters in check and tempts batters to swing at it even out of the zone.

With the Rangers' shaky rotation, Perez has offered consistency and can continue to do so if he continues to fool batters with this powerful, and often underrated, pitch.