How Careful Should the Mets Be With Jacob deGrom in October?

The Mets are the current World Series favorites, with 17.7% odds of winning a championship, according to ZiPS. They have a 76.4% chance of earning a first-round bye through capturing the NL East and a starting rotation fronted by Max Scherzer and Jacob deGrom. In an ideal world, Scherzer and deGrom would pitch every postseason inning, with the occasional Edwin Díaz appearance sprinkled in, because that song with the trumpet is quite a lot of fun.

Unfortunately, people are frail. They’re full of oddly shaped parts that break and swell and stiffen and rupture. Starting pitchers are more susceptible than most. They’re the four-note motif at the beginning of Beethoven’s Fifth Symphony: They come out guns blazing and then need a nice, long break before they’re ready to think about doing it again.

So how should the Mets use deGrom when each out matters more than ever? At a glance, the numbers seem obvious: He hasn’t gone over 101 pitches or seven innings this year, so they could cap him there and be done with it. He’s struggled in the sixth, so they could cap him at five if the game is close. Then again, playoff baseball asks a lot of pitchers. Starters pitch in relief and on short rest, relievers pitch multiple days in a row, closers secure six-out saves. Given deGrom’s long history of injury-interrupted brilliance, the Mets will have a hard time figuring out how far to push him.

This year, deGrom has a 0.83 FIP and a 1.39 xFIP in the first five innings. For starters who’ve thrown at least 30 innings, those numbers aren’t just best in the league this year — they’re the best since 2002, which is the furthest back the splits leaderboard goes. Number two on the list: Jacob deGrom in 2021. In the first five innings of a game, there’s no one you’d rather have on the mound than him.

But at what point would a relief pitcher be an upgrade over deGrom? The Mets have a lights out closer in Díaz, and then they’re heavy on bullpen arms that could fairly be classified as solid but not amazing. Among qualified relievers who are currently on an active roster, Díaz ranks first in FIP. Adam Ottavino, their next best reliever, ranks 43rd. Lefty Joely Rodríguez, their third-best, ranks 95th. Here are their best bullpen options:

And here are deGrom’s 2022 splits by inning and by times through the order:

How much do you trust expected stats? If you go by xFIP, then it wouldn’t be crazy to argue that until the eighth inning or the fourth time through the order, you’d rather have deGrom than a reliever. Seeing as Díaz hasn’t appeared before the eighth inning once this year, give him the ninth and Ottavino the eighth.

Going by runs allowed, though, that would be an insane argument to make. You’d have to go get deGrom before the sixth inning or the third time through the order, whichever comes first. Every reliever on the postseason roster has a better FIP than deGrom in the sixth inning and the third time through the order.

Then again, those are tiny sample sizes. Here are deGrom’s inning splits over the last six years:

He has the best xFIP of any starter in the sixth inning and the fifth-best in the seventh inning. The sample sizes in the eighth and ninth get too small for rankings, but he hasn’t necessarily turned into a pumpkin. At the very least, deGrom has a history of decent performance in the eighth inning.

In the playoffs, the heightened stakes tend to make these decisions much murkier. The numbers, which generally say to go get the ball while the starter is still cruising, are less certain when the starter is an absolute ace. And with the DS and LCS both losing a day off this year, bullpen rest will be at more of a premium than usual.

Complicating matters is deGrom’s health. Every website tracks injuries a bit differently — everybody’s got an injury or two that nobody else lists — and finding exhaustive injury history for deGrom is kind of like tracking down your favorite band’s complete discography. There’s always going to be a Japanese import or a record store day exclusive or a mild groin strain that escapes wide notice. For example: After the 2012 season, deGrom was helping a neighbor castrate a calf when the calf kicked deGrom’s ring finger and broke it. As deGrom didn’t miss any time, neither he nor the calf appeared on an injury report.

Combining injury lists from multiple sources reveals injuries to deGrom’s neck, shoulder, rotator cuff, latissimus dorsi, scapula, triceps, elbow, forearm, lower back, hip, groin, and hamstring. Last year, the Mets shut him down on July 7 due to elbow inflammation. They shut him down this April with a stress reaction in his shoulder blade. He didn’t make his first big league start until August 2, a layoff of nearly 13 months. You have to go back to 2015 for the last (and only) year of his career when his name was off the injury reports entirely.

That was also the year of the Dark Knight. Matt Harvey, returning after 6.9 WAR in 2013 and Tommy John surgery in ’14, blew past his publicly announced innings limit for the season. He convinced manager Terry Collins to leave him in for the ninth inning of Game 5 of the World Series. The Mets lost, and Harvey had thoracic outlet surgery the next season and was never the same. That memory of 2015 looms large.

To complicate matters, deGrom announced in March that he would be opting out of his contract after the season. Rumors about where he’d like to pitch next year are plentiful, but it seems safe to assume that the Mets would like to re-sign him and would therefore presumably like to keep him happy and healthy.

Only deGrom and (possibly) the Mets know how those directives relate to pitching deep into the playoffs. Does keeping him happy mean letting him work his way out of a jam even if it’s the third time through the order, or does it mean protecting him from injury no matter how big the moment? Would he (understandably) place health above all else to avoid jeopardizing his next contract, or might he want the chance to improve his standing on the free-agent market with a display of stamina on the game’s biggest stage?

A further complication is that deGrom had an uncharacteristically bad game on Saturday against the A’s, giving up five runs and walking four batters in four innings, doubling his total for the year. It was the first time deGrom had allowed five runs in more than three years. The Mets are well aware that Scherzer suffered from a dead arm in the playoffs last year, and they’re no doubt on the lookout for symptoms of the same in both of their recently injured aces.

The good news is that deGrom’s struggles weren’t accompanied by any menacing overtones. His velocity, release point, and movement were all in line with his previous starts. But while Saturday’s performance seems to be an outlier, it’s still a reminder that he is less than two months removed from yet another serious injury. Hiccups will happen, because bodies are just unbelievably stupid.

At some point in the next several weeks, the Mets are bound to find themselves in need of a big out. They’ll have to balance the fact that there’s almost no situation in which you wouldn’t want deGrom or Scherzer on the mound with the knowledge that bodies weaken and fail. Hopefully, they can have fun while they do it. After all, what’s more fun than fall baseball?