How the Yankees turned a cast-off bullpen arm into a reliable weapon

MLB: New York Yankees at Kansas City Royals
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The Yankees picked up Michael Tonkin off of waivers in late April, and it was all thanks to a slew of roster moves from two different organizations. The right-hander had been designated for assignment by the Mets, picked up by the Twins, designated for assignment by the Twins, picked up by the Mets again, and designated for assignment again. Before May had even begun, Tonkin was DFA’d three times and would be on his third team, as nobody in the league seemingly believed there was enough value to be had with him.

His first outing for the Yankees did not go nearly as well as he hoped, blowing a 10th-inning lead and then losing the game in the 11th inning, with fans clamoring for him to be DFA’d for a fourth time before the All-Star Break. Fast-forward to today, and he boasts a 0.89 ERA with the team, looking like one of the best bullpen finds in the sport thanks to a couple of key changes.

Michael Tonkin Is Making Some Key Changes With the Yankees

MLB: Minnesota Twins at New York Yankees
Credit: Vincent Carchietta-USA TODAY Sports

With the Twins and Mets, Michael Tonkin used his sinker nearly 59% of the time, and it registered a -4 Run Value over that stretch, even when he first came over to the Yankees he was pretty fastball-reliant. Through his first 15.2 innings, Tokin had a -1.14 Win Probability Added and 13.5% K-BB%, which resembles the statline of a backend reliever who gets released for roster space during the season. His sinker usage was at 59.3% over that stretch, but the Yankees identified that his best pitch was his slider.

Tonkin throws both a gyro slider and a sweeper, and while he mixes in the sweeper occasionally, it’s the tighter gyro slider that he has the most success with since he can throw it to both righties and lefties. Over his last 13.2 innings, he’s increased the gyro slider usage by 11%, decreasing the amount of sinkers he throws and as a result, having far more success on the mound.

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Michael Tonkin is now a pitcher who can pick up strikeouts while keeping the ball on the ground at a high rate, and the Yankees are a team that lacks strikeouts from their bullpen. This isn’t to say that Tonkin will keep up being a sub-2.00 ERA pitcher this season, but his process on the mound is stellar with the increased reliance on his excellent slider. This pitch is truly one of the better breaking balls in the Yankees’ bullpen, as it’s got funky characteristics thanks to its steep movement and its weird release points.

When a pitcher standing at 6’7 is releasing the ball around 5.3 feet from the ground, it can create some serious deception, and the sinker plays more as a set-up pitch for him to throw up and down in the zone where he can pick ups some whiffs or soft contact. It’s a strong arsenal that plays to lefties and righties, and the Yankees once again flex their developmental prowess.

MLB: Spring Training-New York Yankees Workouts
Feb 16, 2023; Tampa, FL, USA; New York Yankees pitching coach Matt Blake (77) and manager Aaron Boone (17) during spring training workouts at George M. Steinbrenner Field. Mandatory Credit: Kim Klement-USA TODAY Sports

It’s a rag-tag group of arms for the Yankees right now in that bullpen, as heroes have emerged in the forms of Luke Weaver and Michael Tonkin, who were DFA’d and considered afterthoughts by many in the league. Cody Poteet has been a nice surprise in their rotation as well, and who could have seen the Yankees getting a combined 2.01 ERA and 24.6% strikeout rate from this group?

Matt Blake and Sam Briend deserve a lot of credit for what they’ve done in this organization, and of course, Michael Tonkin deserves a ton of credit for bouncing back from a tough debut with the Yankees to become one of their most reliable bullpen arms as of late.

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