Zack Wheeler had an interesting 2014

Zack Wheeler had fairly a solid season in 2014. He’s now had a year and a half of generally successful major league time, though he’s still not the front-line starter that many had predicted he could become. He’s still very young and has plenty of time to improve, but that doesn’t mean we can’t drill down into his 2014 a bit to get idea of what kind of pitcher Wheeler is at this point. Let’s take a look at a selection of his 2014 statistics, broken down by month.

The main thing that pops out here is that Wheeler was kind of all over the place. To be fair, anytime we start examining performance in such small chunks (in this case samples of 5-6 games) we’re bound to see significant levels of variation. But in Wheeler’s case, he almost becomes different pitchers.

He started the year out well, outperforming his ERA with a great strikeout rate. He was a tad unlucky with a slightly above-average BABIP and the hits plus his average walk rate led to a pretty mediocre WHIP. Still, there were positive signs to start his sophomore season. He didn’t build on his strong debut in May, however, striking out fewer batters while walking more. While his BABIP regressed to the norm a bit, his LOB% dipped as well, suggesting he was just simply not getting the outs he needed. This was further supported by the absolute nosedive of his FIP.

There were more positive signs in June, as he struck out more batters while walking slightly less. His FIP rebounded and his WHIP was average to above-average. The significant drop in SLG and HR/9 suggested that he was giving up weaker contact, a positive sign for a pitcher who seemed dead-set on striking everyone out. Still, major improvement for Wheeler would need to be accompanied by a decent reduction in walks.

Then July rolled around and things got weird. He struck out fewer batters, continuing the seesaw, but he also dropped his walk rate by almost two batters per nine innings when compared to May and June. His SLG increased by nearly 100 points and his HR/9 spiked as well. He was essentially a different pitcher than he was up to that point in the season. His ERA and WHIP were great, but there were two other contributing factors beyond the sharp decrease in walks. His BABIP dropped below average for the first time during the season. He was a bit lucky, but not too abnormal. His nearly 96% LOB% was ridiculous, though.

Did Wheeler make any major changes that led to this odd month? The chart below was pulled from Brooks Baseball and breaks down his pitch usage throughout the year.

It seems as though Wheeler relied more heavily on his fastball/slider combo in July. Additionally, as the following charts (also from Brooks Baseball) indicate, there was a simultaneous increase in fly balls and decrease in line drives against his slider.

Was this perhaps the result of the refinement of his slider and/or better situational usage? It’s possible, though more likely it was purely luck based on his LOB% and BABIP. We can’t really consider that LOB% anything but an obscene anomaly. Interestingly, there was a sharp decrease in his use of the slider and fastball in August. He was walking too many batters and was the beneficiary of that low BABIP again. He closed out the year fairly strong, taking his strikeout rate above 11 per nine innings while once again reducing his walk rate.

It’s clear that Wheeler will need to bring that walk rate down if he’s ever going to be that top of the rotation starter we all hope he can become. It’s still very early and he has plenty of time to refine his pitches as well as his approach. His roller coaster 2014 indicates that he’s still got a ways to go in both areas, though.