Pittsburgh Pirates: JT Brubaker Riding His Sinker to Success

JT Brubaker has been arguably the best starting pitcher for the Pittsburgh Pirates this season and much of his success can be contributed to his sinker

Pittsburgh Pirates right-handed starting pitcher JT Brubaker has come out of the gates hot in 2021. Through his first 5 starts and 27.1 innings, Brubaker has a 2.63 ERA, 3.90 FIP and 1.03 WHIP.

Brubaker has walked just 4.4% of all the batters he has faced while having a 26.5% strikeout rate. Brubaker’s K/BB ratio of 6.0 currently ranks 20th among the 102 pitchers so far in 2021 to throw at least 20 innings.

To go with his strong bottom-line numbers, Brubaker also has some good ERA estimators. He’s currently holding a 3.19 SIERA, 3.20 xFIP, 3.58 xERA and 3.19 DRA. He’s also induced ground balls at an insane 54.2% rate. However, a large part of his success has been because of his outstanding sinker.

Brubaker’s sinker has easily been one of the best offerings in the major leagues. Currently, it sits with a -5 run value, which ranks 36th in all of baseball. In terms of run value per 100 offerings, he ranks 9th with a -7.1 mark. Brubaker’s sinker leads all other pitchers who use a sinker in RV/100 and is tied for 3rd in overall run value. He’s tied with Steven Matz, Adrian Houser, Marcus Stroman, and Logan Webb.

Batters have barely been able to hit the pitch. Entering his start on Friday night hitters managed a batting average of just .050 against the offering and have a sub-.200 wOBA against it at .196. His wOBA against ranks 9th among all sinkers in 2021 while his opponent average is far and away the best among all pitchers who have thrown it in at least 20 plate appearances.

He also has a very strong .206 xBA and .273 xSLG with his sinker. Both rank within the top 35 sinkers in baseball. Opponents only have a 28.6% hard-hit rate, the 30th best mark among sinkerball pitchers. All three of his whiff (19.4%), strikeout (23.1%) and put away (25%) rates are above average. Impressively, the average launch angle has been -2 degrees. Not only is he getting a ton of ground balls, but opponents have just an 85.7 MPH exit velo vs the pitch. Batters are swinging and missing at Brubaker’s sinker at an above average 19.4% rate. He has also put away a quarter of all batters with his sinker.

Overall, this is a massive step-up compared to 2020. During his rookie campaign, Brubaker’s sinker was much less effective. Opponents had a .266 batting average and a .438 slugging percentage against this offering. His whiff rate sat at just 17% and he put away just 15.3% of the batters he faced with it. All told, the .330 wOBA batters managed against the offering show just how ineffective he was at times with his sinker.

Likely the main reason he’s gotten way better results with this pitch in 2021 is because of his overall pitch usage. Brubaker threw his sinker 35.1% of the time in 2020, making it his most used offering. However this year, it’s his third most used offering as he’s tossed it 22.3% of the time. He’s mixing in his slider much more at 34.9%, his most used pitch. He has used his four-seam fastball more often as well, at 24.5% compared to 13.9% in 2020. He is using three pitches at least 20% of the time compared to just 2 pitches in 2020.

Brubaker is looking much better in 2021 compared to 2020 and a big part of his success has been him being able to induce way better results with his sinker. Though it is his third most used pitch in 2021 compared to his most used pitch in 2020, changing the amount of usage may have just helped him.