Microtrends: Kevin Gausman's Weak Contact

Since he moved into the Orioles' rotation again, Kevin Gausman has pitched to mixed results. He's put up an uninspiring 4.26 ERA in his ten starts, albeit with a 3.78 FIP. His strikeout rate has jumped from years past, to a solid 21.0%, and he's issued free passes at a meager 4.7% clip; however, poor sequencing (as evidenced by a 67.5% strand rate) has done him in. Taking into account his past performance, though, I found one element of his 2015 starts especially interesting.

Gausman only started five games in 2013, all of which went pretty disastrously — he allowed 21 runs in 24.2 innings, chiefly because of a .351 BABIP. Becoming a starter full-time in 2014, he improved considerably in terms of preventing runs, with a 3.57 ERA across 20 outings. That came despite a subpar .304 BABIP, indicating that hitters still hit the ball hard against him. Over his first 25 career starts, Gausman gave up a hit on 31.3% of the balls put in play against him, a rate that didn't bode well for the future.

The future, as they say, is now. Gausman's 2015 starts have seen him limit the opposition to a .264 BABIP — tremendously lower than we'd expect based on his history. Unlike strikeouts and walks, balls in play take a long time to stabilize, so this could dissipate over a larger sample. The descriptive measures here, though, would suggest that Gausman's weak contact will remain.

By the various batted-ball statistics FanGraphs provides, Gausman has upped his game in virtually every regard:

Starter	LD%	GB%	FB%	PU%	Soft%	Med%	Hard%
2013-2014	24.2%	40.5%	32.4%	2.9%	14.6%	54.3%	31.2%
2015	18.8%	41.9%	33.3%	5.9%	26.3%	46.8%	26.9%

Fewer line drives and hard-hit balls, along with more popups and soft-hit balls, will generally lead to a depreciated BABIP. That's held true for Gausman, whose process has changed to create these results.

In his 2013 and 2014 starts, Gausman relied primarily on three pitches: a four-seam fastball, a slider, and a splitter. The former occupied 68.3% of his overall pitches, while the usage rates for the latter two came in at 8.0% and 18.0%, respectively. He's thrown the fastball just as often during his 2015 starts — a 68.2% clip doesn't differ much at all from the mark he established prior. His shiny new curveball has slid in nicely, replacing the slider with a clean 8.0% usage rate. And the splitter has remained a solid secondary offering, at 16.2%. Which of these three pitches has helped him the most?

The four-seamer, and it's not very close. Hitters battered the slider for a .392 BABIP, and their current .375 figure against the curveball conforms to that. The splitter's .298 BABIP before 2015 has also remained stable, at .290. By contrast, 31.1% of Gausman's four-seam fastballs in play used to go for hits, whereas 24.8% of them have done so thus far. That massive drop accounts for almost all of the variation in Gausman's BABIP, meaning that fastballs have made the difference.

Earlier this year, Jeff Sullivan observed that Gausman had started to throw more high fastballs. That trend from Gausman's bullpen time has carried over to his tenure in the rotation:

First image includes all 2013-2014 appearances.

The higher fastballs have consistently gone for fewer hits when put in play, so increasing their quantity means Gausman's been able to suppress the BABIP against him. Even at the major-league level, most hitters really can't make solid contact on a high heater in the upper 90s; Gausman appears to have realized that, at long last.

Gausman will take the hill tonight against the Rangers, hoping to sustain Baltimore's faint postseason dreams. He may allow some hits on balls in play — over the long term, very few (if any) starting pitchers can maintain a BABIP in the .260s. But this profile shows that he can continue to turn balls in play into outs; if he starts to strand runners as well, he could become Baltimore's next overperformer.