Mets: How Mickey Callaway should use Robert Gsellman

The New York Mets will likely use Robert Gsellman in later innings once again this season. However, some splits hint at who it is he should be facing.

Robert Gsellman‘s first appearance for the New York Mets signified a change in fortune for the 2016 season.

The Mets were reeling. Three days before the All-Star Break they were 47-39, but now their record stood even at 62-62 in late August, a massive 3-game set in St. Louis–whom the Mets trailed in the Wild Card race by 4.5 games–on the horizon. This was a season in which Logan Verrett started 12 games, 43-year-old Bartolo Colon led the team in innings pitched, and James Loney manned first base 88 times too many. It was weird.

On opening night of the Cardinal series, Jon Niese manned the mound for his would-be final start as a Met. After being gifted a lead by Wilmer Flores‘ 3-run shot in the top of the first, Niese flushed it away thanks to 21 detrimental pitches–a mere 10 of them strikes–and a knee injury.

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Gsellman entered in the first with one out, limited the damage, and threw exactly half–75 out of 150–of the bullpen’s pitches to will New York to a 7-4 win.

Gsellman was an enormous piece of the Mets’ ragtag Wild Card club in 2016. He threw 44 2/3 innings with a 2.42 ERA and 1.2 WAR and made six starts in September in which the Mets went 4-2. Gsellman’s 2017 campaign, however, was hopeless; in 22 starts and 120 innings he put up a 5.19 ERA with a miserable 14.9 K% and 1.50 WHIP.

A New Role for the Mets

In 2018, new manager Mickey Callaway experimented with Gsellman in the bullpen; sometimes as a long man, sometimes as a late-inning stopper, and sometimes as the closer.

Gsellman’s performance last season falls right between his 2016 and 2017 campaigns, so maybe this exercise will be ultimately meaningless. Perhaps last year’s Gsellman–at least statistically–is what we should expect from now on; his 2018 ERA (4.28) practically matches his career mark (4.38), as does his soft contact rate (19.4% in ’18, 19.5% in his career). That said, Gsellman is only 25 and under team control until at least 2023.

Figuring out the best way to use him could be crucial for the Mets in 2019. Despite bringing back Jeurys Familia and adding Edwin Diaz, the rest of the projected bullpen remains somewhat foggy. While Gsellman now has some backend experience, he will no longer be tied to the most difficult relief tasks now that New York’s bullpen has improved.

Splits and Sequences

Gsellman did the bulk of his work in the 7th, 8th, and 9th innings last season, but he’ll likely pick up more opportunities earlier in games in 2019. Last year, Gsellman had a 5.02 ERA in the 7th inning (14 innings) and a 5.93 ERA in the 8th (27 innings), but a deeper dive suggests that Gsellman’s struggles can be attributed not to the moment in the game, but to the hitter at the plate.

Gsellman faced 345 batters last season over the course of 80 innings pitched. He faced middle-of-the-order (3, 4, and 5) hitters 116 times and all other hitters 229 times. The difference in outcome between those two groups is staggering:

1, 2, 6, 7, 8, and 9 hitters against Robert Gsellman in 2018
- .208/.274/.307, 229 PA, 18 BB, 42 H, 5 HR, 4.3 XBH%
- 3, 4, and 5 hitters against Robert Gsellman in 2018
  - .333/.405/.529, 116 PA, 10 BB, 34 H, 3 HR, 11.2 XBH%
  In terms of on-base and slugging, above is essentially the difference between Orlando Arcia and Alex Bregman.
  Gsellman only allowed 8 home runs last season to 8 separate hitters who combined for a mere 112 dingers on the year. Gsellman finished his season with a 2.3 HR%, 0.8 percentage points better than the league average for pitchers. However, he struggled to keep middle-of-the-order hitters from hitting for extra bases. In a vacuum, it seems that 3, 4, and 5 hitters are the bane of Gsellman’s existence. Check out his career numbers with the same split as above:
  - 1, 2, 6, 7, 8, and 9 hitters against Robert Gsellman in his career
    - 700 PA, .356 SLG, 6.3 BB%
    - 3, 4, and 5 hitters against Robert Gsellman in his career
      - 379 PA, .521 SLG, 10.8 BB%
      It’s clearly burdensome for Gsellman to face cream of the crop hitters, but the nice thing about being in the bullpen is that a manager can tweak who you face and when you face them.
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      It would be beneficial for Mickey Callaway to dive deep into Robert Gsellman’s stats and figure out how he can be used most effectively. It would help the Mets, too.

The New York Mets will likely use Robert Gsellman in later innings once again this season. However, some splits hint at who it is he should be facing.

More from Rising Apple

A New Role for the Mets

Splits and Sequences

Schedule