Assessing the 2017 Value of Kevin Gausman

There are only so many stones to overturn with waiver wire suggestions for the stretch run and only so many strategical quirks to point out, too. With that in mind, I’m going to turn my attention to 2017 — sort of. As Jeff Zimmerman recently pointed out, Kevin Gausman is shoving in the second half. Jeff noted the biggest change between halves is an improved LOB% and a drop in HR/9. Combing over his PITCHf/x data, there’s something I’ll be keeping tabs as the season winds down.

Have I mentioned I love the new interactive splits tool? No? Well, I do love it. After seeing Gausman’s monster second-half numbers (2.73 ERA, 3.79 FIP, 3.63 xFIP, 1.25 WHIP and 27.1% K) when perusing the pitcher leaderboard, I immediately headed to his player card to see how he’s fared against righties this year. The answer is poorly. He’s yielded 16 homers, a .495 slugging and .358 wOBA to the 332 of them he’s faced this season. Has he improved against them in the second half? He hasn’t improved much. The righty has coughed up five homers, a .467 slugging and .352 wOBA to 118 rigthies in the second half.

But has he had any good months against them? Yes, he has. In fact, his dreadful full-season totals against righties are largely inflated by his struggles in May and July (12 homers, .664 slugging and .436 wOBA allowed to 149 righties, in those two months). In the months of April, June, August and September, he’s faced 183 righties and allowed just four homers, a .359 slugging and a .296 wOBA. I’m not cherry picking these time frames to suggest he can settle in as a pitcher who holds righties to a .296 wOBA. Instead, I wanted to see if his pitch mix during his good and bad months revealed any explanation for his ups and downs.

I can’t break his PITCHf/x data into May/July and April/June/August/September, but I can look at the PITCHf/x data in the game log section, and that works. It looks like the movement on his slider is more consistent in the second half. Take a look at the horizontal movement on the slider for each of his starts in the first half. Now, take a look at the horizontal movement on it in his starts in the second half. The horizontal movement is more tightly clustered in the second half. The vertical movement is almost identical overall between halves (-2.1 in the first half and -2.0 in the second half), however, once again the movement is more tightly clustered in the second half than in the first half. Gausman has allowed multiple homers in five games this year. In three of those contests (5/26, 7/1 and 7.29), his slider’s vertical or horizontal movement sat at one extreme end of the spectrum. His slider featured the least horizontal movement of the year (0.4) in his 7/1 and 7/29 starts and the most horizontal movement (4.1) in his 5/26 turn. His vertical movement was all over the map in those starts. Perhaps he was struggling with the feel of his slider in those turns, but I’m not sure.

It seems plausible that the more tightly clustered movement in the second half could represent improved feel for the pitch. Pitch classifications are tricky, and Brooks Baseball credits Gausman with primarily throwing a curve and not a slider (they have classified just 28 of his pitches thrown to righties as sliders this year, and all were thrown in May — remember, May was one of his two troublesome months with righties). Thus far this month, 23.26% of Gausman’s pitches to right-handed batters have been curves (which I refer to simply as breaking balls or breakers to avoid classification confusion), per Brooks Baseball, his second-highest usage rage in a month this year trailing only his two starts in April (28.81% usage). His two lowest usage rates of the year came in — surprise, surprise — his two worst months against righties (May and June). Even if you combine his curve and slider usage rates versus righties in May, the usage rate would be his lowest in any month of the year.

So, clearly the breaking ball has turned into a weapon against right-handed batters, right? Not exactly — at least if you look at the results on the pitch in the first and second half. His batting average and ISO allowed to righties on the pitch is higher in the second half than in the first half. However, the pitch has kept righties in check since the beginning of August! From August 1st until today, he’s allowed just a .235 batting average and .059 ISO on the curve to his same-handed foes. He’s tallied a 19.70% whiff rate on the pitch during that time frame compared to a 14.09% prior to August, and the groundball rate on the pitch is strong at 53.85% over the last month and change.

As his breaking ball has fared better against righties, his splitter has as well. Prior to August, righties hit .290 with a .355 ISO and 29.41% whiff rate against the splitter. From August until today, he’s tied righties up with the splitter allowing just a .067 average and .067 ISO with an eye-popping 40.98% whiff rate. As it stands, Gausman should be a helpful starter the rest of the year and next season. If he’s truly improved his breaking ball and his splitter is going to play up, too, the 25-year-old could springboard his big finish into a monster full season next year. I’ll be monitoring his breaking ball usage and results the rest of the year.