Zac Thornton Is Surviving, But His Margin For Error Is Getting Smaller

[Yirsandy Rodríguez]

Image courtesy of © Wendell Cruz-Imagn Images

Since Zac Thornton came back from the injured list, he has pitched to a 3-3 record with a 2.42 ERA in 10 starts with the New York Mets. He has achieved part of that dominance with a strikeout rate of 6.4 K/9, the second-lowest among the 14 starting pitchers who have accumulated at least 50 innings and a 2.40 ERA or lower in the same span. Only Brandon Pfaadt, the right-hander of the Arizona Diamondbacks, has had a lower strikeout rate (5.5).

I’ll start by saying that I love Thornton and value what he has done to recover and return to the mound. He has personality, attacks the strike zone, and possesses an interesting combination in his stuff. However, although I want to be optimistic, I think he has lived on the tightrope for too long. His four-seam fastball and his sinker do not impose themselves enough to garner tremendous respect. That makes him a vulnerable pitcher and, at the same time, dependent on his defense, which is fatal in many situations where he needs to avoid contact. I firmly believe that this version of dominance that we are seeing will not remain for long if Thornton does not begin to make immediate adjustments.

During August, he has thrown fastballs 72.6% of the time when batters have been ahead in the count. What has been the result? He has allowed a .561 xSLG in 25 plate appearances.

The distribution of his repertoire reveals a contradiction. Thornton is building his strategy based on the cutter and the four-seam fastball, but those have been the pitches that are generating the fewest swings and misses. Instead, the sweeper and the curveball, which he usually uses to attack the corners and try to get ahead in the count, are his pitches with the best results.

That said, there is something very clear here: batters know that Thornton does not have high velocity on his fastball, which gives them some margin of error to better identify his pitches. Where Thornton has the advantage is in the command of his pitches.

The +10 run value that Thornton has gotten in the heart of the zone also helps to understand how he is surviving with so few strikeouts. He has generated +6 runs of value when batters swing and another +4 when he decides to attack the zone without being punished, which is allowing him to move ahead in counts. However, we have a bigger problem here: the disadvantage in his profile against right-handed batters.

While Thornton has held left-handed batters to a line of .194/.239/.239 and .218 BABIP, right-handers are doing the most damage with a .273/.325/.424 slash and .308 BABIP. The following graphic better describes where his pitches have been more exposed against right-handed batters.

Thornton is working the edges of the zone better, where he has limited the average. But in the middle is the warning: they have hit him at just .227, while the xBA is .401. He is getting very favorable results in an area where the quality of the contacts should be favoring the batters much more. He has also had luck when they hit the pitches in the high corners, inside and outside, with differences of .128 and .198, respectively. Once the pitches move away at the edges of the strike zone, the expectations change noticeably.

Frequently, right-handed batters are being more aggressive against Thornton the first time they see his pitches in the game. They are also producing more frequently, recording a rate of 16.0 HR/FB%. Then, they have adjusted their swing and, for the second time they face him, their O-Swings% rate has fallen by 8.0%. They hit more line drives as well, yielding a quality in the contact that has also caused the reduction in the K/BB rate from 3.00 to 1.86.

So, it is clear that Thornton is not going to overcome most of the problems with his fastball with much more velocity. Although it was good news that his four-seam fastball reached the highest peak in velocity (93.1 mph) during his most recent start, when he threw six innings and left the Milwaukee Brewers at one run this past Tuesday, Thornton will have to redefine his attack strategy, especially against right-handed batters. He has a good reason to trust more in the consistency of his secondary pitches, which could prove the next stage in his evolution as an MLB starter.

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[Centerfield]

I think the conclusion of this article is that Zac can be a productive MLB pitcher. I hope so. 
 

I realize he doesn’t throw that hard by today’s standards, but soft tossing lefties have been successful since MLB began. I don’t see why that can’t be true now. 

Plus 92-93 is not uncompetitive.