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Grading the Mets’ Luis Severino signing

High risk, high reward gambles like this are exactly how you want to fill out the back of the rotation.

Milwaukee Brewers v New York Yankees Photo by Rich Schultz/Getty Images

David Stearns’ first major move as the Mets’ president of baseball operations was to sign Luis Severino to a one-year, $13M deal. The formerly longest tenured Yankee heads across town on what is essentially a pillow contract as he looks to rebuild his value after several consecutive injury plagued years.

Severino was once one of the better starters in baseball, putting together a two year stretch between 2017 and 18 where he tossed 384.2 innings of 3.18 ERA ball, running a 10.53 K/9 with a 3.01 FIP and a 76 DRA-. In that stretch, he was worth between nine and eleven wins—depending on your WAR metric of choice—and finished top-10 in the Cy Young voting in both years.

Since then, the 29-year-old righty has thrown only 209.3 innings across five seasons. His 2019 was wiped out by rotator cuff inflammation and a lat strain, his 2020 by Tommy John surgery. He had a bumpy rode back and made only four appearances in 2021. Another lat strain cut his 2022 in half, and his 2023 season was ended after an oblique injury in early September. His performance when healthy hasn’t been particularly even either; he looked almost like himself in 2022 - 3.18 ERA, more than a strikeout per inning - but was an absolute disaster in 2023, with an ERA approaching seven.

Clearly the Mets are hoping for something more akin to his time as a top-of-the-rotation starter. Much of the outcome here will depend on health, but Jeremy Hefner and the rest of the coaching staff are also going to have to figure out what went wrong under the hood for Severino last year to send him off the rails. It’s not a straightforward answer either. Here are the metrics on Severino’s primary offerings in 2018, 2022, and 2023:

He’s obviously lost some juice from his 2018 peak, particularly on his fastball and slider. He’s also picked up a new cutter, one that has continued to rise in usage in place of his fastball, slider, and changeup. The changes from his 2022 profile aren’t actually that significant, with one exception - his fastball gained 1.2 inches of drop, which is to say it lost a some amount of rise. That might not sound like a lot, but it shifted the vertical attack angle (VAA) on the pitch roughly 0.2 degrees relative to average, and that’s a notable enough change to have an effect. Correspondingly, batters had a .468 wOBA against his primary offering in 2023 after posting a paltry .284 mark in 2022.

Getting Severino back to a slightly flatter attack angle would be a good tweak, but I don’t think it’s the whole story. There’s a much more universal change that likely effected Severino’s stuff across the board. Below on the left, you can see Severino’s zone profile from 2022, with his 2023 zone profile on the right:

While the general areas that Severino likes to hit are the same, there’s clearly an overabundance or red in the middle of the zone in the 2023 plot. Obviously that’s not where you want your stuff to be ending up, and Severino got hammered when throwing pitches over the heart of the plate.

You can take this one of two ways I think. An optimist might posit that Severino’s 2023 struggles were simply an issue of control. With the quality of his stuff largely intact, the #3 or better quality starter we saw in 2022 is still in there and relatively attainable. The more pessimistic among us - and let’s be honest, that’s most of the Met fan population - will worry about how feasible regaining that control actually is.

My amateur eye could not identify any clear mechanical differences when comparing Severino’s 2022 and 2023 tape. Per Brooks Baseball, there was a small but notable shift to a more sidearm delivery in 2023, with all his offerings coming out roughly 2-3 inches closer to the third base side. That could be a fixable issue, or it could also be an indicator of a shoulder injury leading to a loss of Severino’s standard mechanics. It’s impossible for us to determine which is the case without access to Severino’s medicals of course, but the idea that a pitcher with as lengthy an injury history as his over the last half decade is suffering some lingering effects is not exactly surprising.

There are undoubtedly further aspects of Severino’s profile that could be dissected further, but these details are ultimately window dressing. The Mets signed a pitcher with obvious upside to an affordable, one year deal. The downside risk is minimal, while the payoff is potentially huge. More importantly, you’d rather the Mets fill out the rotation with this type of risk-reward profile rather than guaranteeing a spot to pure innings eaters who will simply not be very good (your Kyle Gibson or Jordan Lyle types). Given that there are no glaring flaws that suggest Severino is completely lost cause, there’s very little to nitpick with this move in a vacuum. As such, it receives an A.