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A call for pitchers to stop throwing sinkers

It isn’t working.

Seattle Mariners v Houston Astros Photo by Bob Levey/Getty Images

Yesterday, while perusing the internet for ideas for this scheduled piece that you are reading right now, I came across Joe Biagini’s Brooks Baseball page. If you paid attention to the trade deadline, you’d know that Biagini was recently traded away by the Blue Jays and acquired by the Astros to help with an already good bullpen. If you’ve followed baseball for the past couple seasons, you’d expect immediate improvement out of Biagini due to changes made by a bright Astros developmental staff. Anyone could’ve guessed that the Astros would probably tinker with his pitch usage, his release points, maybe his grips on the ball. I expected to see something along these lines when looking at his numbers. Here’s what I saw.

Welp. If there is a visual that says screw the sinker more than this one, I have yet to see it. In his few appearances with his new team, the Astros intent here seems clear as day. Stop throwing your worst pitch. Mix in something different. He’s essentially abandoned a pitch that he added to his repertoire back in 2017, one that he threw at a fairly high rate with the Blue Jays this year (43.5 percent). He’s flipped the usage on that pitch with a once rarely-used four-seamer (5.2 percent with the Blue Jays, 42.9 percent with the Astros).

Admittedly, we have yet to see reliable results produced by this significant change, considering that Biagini has only appeared in three games with the Astros. The outcome feels all too predictable though.

After looking deeper into the numbers, one would wonder why this change took so long to happen. The sinker has been Biagini’s most used pitch the last two seasons. It has also been his worst pitch, by a significant margin. Thanks to an above-average array of secondaries, he’s been able to work around this to become a serviceable pitcher. But logic would suggest this was severely limiting the ceiling in his performance.

To be fair, this problem with sinkers isn’t just catered to Joe Biagini and the Blue Jays. It’s almost league-wide. There have been 105 pitchers with at least 100 results on their sinker this season. Eighty-two of them have allowed an above-average xwOBA on the pitch. Their median-xwOBA is .370. There are probably only a few pitchers that you could say have had a significantly good sinker this season (Aaron Bummer, Jordan Hicks, Matt Albers, Kyle Ryan). But Biagini and a few other cases should be the final nail in the coffin for the sinker.

I examined the 10 biggest decreases in sinker usage among qualified pitchers this season. Their median xwOBA in 2018 was .340, considerably above league-average. All 10 of these pitchers either eliminated or nearly-eliminated the sinker from their repertoires this season. The median xwOBA of these 10 pitchers for the 2019 season is now .299, considerably above league-average. Other notable cases that can perhaps attribute their improvements to ditching the sinker include All-Star Lucas Giolito and Martin Perez.

Overall results of the biggest decreases in sinker usage

Name 2018 xwOBA 2019 xwOBA
Name 2018 xwOBA 2019 xwOBA
Jake Diekman 0.311 0.300
Andrew Cashner 0.358 0.354
Kelvin Herrera 0.298 0.341
Martín Pérez 0.364 0.298
Dylan Covey 0.329 0.400
Austin Brice 0.326 0.280
Michael Lorenzen 0.320 0.288
Tyler Duffey 0.373 0.275
Jeff Samardzija 0.365 0.316
Lucas Giolito 0.350 0.282
Median 0.340 0.299
FanGraphs, Baseball Savant

Why there is still a sinker usage issue in baseball, I don’t know. I do know for some pitchers that it’s probably not as simple as ditching the offering. Some may not have an amicable alternative, some may still value the pitch for sequencing purposes. But data suggests that there are still far too many sinkers being thrown and a few case studies suggest that it is probably hampering the performance of many pitchers.

Patrick Brennan loves to research pitchers and minor leaguers with data. You can find additional work of his at Royals Review and Royals Farm Report. You can also find him on Twitter @paintingcorner.