Martin Perez: Bad Fastball, Awesome Sinker

You can look at parts of Martin Perez’ profile and find yourself salivating over the upside. At the same time, there are parts of his profile that can make you question whether he’s a major sell-high candidate. Ranked around the 100-mark entering the season, Perez seems closer to proving doubters wrong but hasn’t yet validated believers.

To wit: Perez isn’t striking many batters out, but he’s not walking many, either; He’s improved his ground ball rate, but he’s also been gifted a 0.0 percent HR/FB mark; and he has a 1.86 ERA, one that’s surely helped owners early, and it’s backed by a healthy 2.42 FIP and 3.20 xFIP, but ZIPS and Steamer don’t like him any better than a 4.38 and 4.68 ERA, respectively, for the rest of the season.

The good-and-bad profile gets even tougher to figure out when you dive in deeper.

To illustrate how tough it is to get a handle on Perez at present, I’m just going to throw a few numbers and ranks out there (ranks are sort descending, so ranking first in Contact allowed would be bad but ranking first in O-Swing would be good):

Statistic	2014 Value	2014 Rank (of 109)	Career
LD%	20.80%	44	20.80%
O-Swing	33.50%	21	29.6
Z-Swing	61.60%	58	64.8
Swing	44.70%	70	45.8
O-Contact	65.00%	41	64.4
Z-Contact	93.90%	9	89.1
Contact	80.90%	39	80.5
Zone	40.00%	106	46.2

I really just included the line drive rate to indicate that despite the high ground ball mark, some solid contact is still being made, about in line with his career mark so far.

It’s the plate discipline profile that’s far more interesting, however, as, like with everything else, Perez is doing some things well and others…not so well.

Primarily, Perez is doing a terrific job inducing swings on pitches outside of the zone. Unfortunately, he’s throwing way too many pitches out of the zone, ranking almost dead last in zone percentage. That’s a dangerous line to toe and one that makes his current 6.7 percent walk rate seem precarious. You can forgive the high out-of-zone approach given that the O-Swing is so high, except that batters are making contact on those out-of-zone swings at a well above-average rate. Batters are 9-for-54 putting pitches outside of the zone in play, which is fine, but they’ve also whiffed “just” 38 times on 121 swings out there (a good rate but maybe not enough to justify throwing it out of the zone so frequently).

As a comparison, Jordan Zimmermann, who has similar O-Swing and O-Contact marks, has allowed hitters to go 5-for-34 on pitches out of the zone but has also managed to get 23 whiffs on just 58 swings. Perez compares favorably to an Eric Stults or Wade Miley when it comes to whiffs out of the zone, but Perez is also wasting far more pitches than two of those three comps (per BaseballSavant):

Pitcher	> 1ft from center	Pitches	% Vert Wasted
Stults	96	339	28.32%
Perez	96	400	24.00%
Zimmermann	73	331	22.05%
Miley	88	478	18.41%

Perez misses a great deal of pitches that aren’t even close, in horizontal terms. It’s not surprising to see that Stults has a similar low-strikeout mark despite a good O-Swing mark, given that he’s missing wide even more frequently than Perez.

Do you know why this is frustrating? Because of the top-50 qualified pitchers in terms of O-Swing rate, Perez ranks 36th in strikeout rate. Generally, pitchers getting that many swings out of the zone are getting strikeouts. The average swinging strike rate for that group of pitchers is 10.56 percent, well above Perez’ 8.3 percent. The result is that, despite the strong O-Swing rate, Perez isn’t even a strong candidate for a strikeout rate surge because, again, he’s not getting swings and misses and he doesn’t throw the ball in the zone much.

At the heart of the lack of whiffs could be a weak fastball. Per Brooks Baseball, Perez has thrown his four-seamer 126 times this year, coaxing just a 4.26 percent whiff rate, which is anaemic. His velocity is down from 93.9 MPH to 93, which wouldn’t be that concerning early in the year except that his velocity has also declined with each start.
As troublesome as the heater is, his primary offering has been excellent (like I said, this is a very good-and-bad profile we’re dealing with).

His sinker, which he throws more often, has been at the root of his ground ball surge – it gets ground balls on 63.2 percent of balls in play, even better than the 49.5 percent league average on sinkers – and its 17.4 percent whiff rate is better than the league average for sinkers, too. The sinker’s been a very good pitch for him, and he may actually want to lean on it more, considering nobody is missing his four-seamer. He can’t really seem to control the four-seamer all that well, either, missing “bad” horizontally 33 times already this year.

The end result of all of this is somewhat unclear. Perez has one of the most effective sinkers going at present but one of the least effective four-seamers, though he seems to be realizing this, firing 50 sinkers in his last outing, a complete game shutout. If that’s a change that’s going to last, Perez seems as much a “buy-high” as a sell-high. If he’s going to revert to splitting four-seamers and sinkers evenly, like he did against Houston on April 13 – he had just two strikeouts against the league’s most strikeout-prone team – then it’s less clear.

In particular, he’s thrown the fastball on 28 percent of first pitches with 11 balls to 14 strikes (and four balls in play), compared to leading with the sinker 34 percent of the time for 12 balls to 19 strikes (and five balls in play).

Perez is slated to pitch on Wednesday against Oakland, a team that doesn’t strike out much in the early going and has also had some success against sinkers. It will be an interesting test for Perez and provide us with a little more information as to how he plans to attack moving forward – if he’s going to keep leaning on the fastball, especially early, there’s reason for concern. If it’s the pitch mix we saw in his last turn out, there’s little reason to sell-high.

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