Pittsburgh Pirates: Sinker Powering Mitch Keller’s Recent Success

Mitch Keller added a sinker to his arsenal late in May, but can he sustain the success he has earned from it so far?

It’s been a rough go of things for Pittsburgh Pirates right-hander Mitch Keller in his young major league career. He’s struggled with command and consistency, which has led to a disappointing career so far. But the Pirate right-hander is trying to salvage what he can. Keller recently added a sinker to his arsenal, but can he ride this pitch to success?

Keller threw a sinker for the first time in his MLB career on May 18th. He only threw it once and hit a batter but used it a lot more in his second outing. With a 33.3% usage rate, it was the first time Keller threw another pitch more often than his fastball during a game. He only let up one hit when he used it. In his third outing, Keller used his newly found sinker 34.7% of the time and let up just one hit again. The downside is he also walked four guys.

Keller’s sinker usage reached its peak in his start against the Detroit Tigers. Again, he let up just one hit while using it 44.4% of the time. Keller’s fastball usage dropped below 10%, down to 7.4%. Both his slider and curveball were being used more often than his four-seamer.

Although it’s a small sample size, Keller has been very effective with his sinker this year. Opponents have managed just a .233 batting average and a .267 slugging percentage against the offering. When they have made contact, he’s induced mostly soft contact. The average exit velocity his sinker has generated comes in at 83.7 MPH.

Keller’s sinker has already become one of the best in baseball so far. With a -3.8 RV/100, Keller sits in 19th place in RV/100 among sinkers. Entering Sunday, since making his sinker his primary pitch, Keller has a 2.75 ERA, 19% walk rate, and 10.7% walk rate. In Keller’s defense, five of the 12 walks he has surrendered came against the Dodgers, and he has countered unimpressive walk rate and strikeout rate numbers by inducing a 53.5% ground ball rate.

Keller added on six more quality innings after Sunday’s start. He did walk three batters and only struck out four, but he allowed just a single earned run on three hits. Keller’s quality outing against the San Francisco Giants was the fourth time he went 5+ and allowed two or fewer earned runs in a row. It is the first time in his career he’s done that for three or more straight games.

Maybe the groundball approach is what Keller needs. Maybe he can have better command over his sinker than his fastball. Only time will tell, but so far, Keller’s sinker has helped him improve a vast amount. He might not be getting a ton of strikeouts, but he’s getting outs at a respectable rate and putting up pretty good numbers to serve as the 5th man to a quality rotation for the past month-and-three-quarters.