Grading the Mets’ Starling Marte signing

In a dramatic close to their Black Friday shopping, the Mets secured their biggest prize, adding Starling Marte on a four-year, $78M deal. Coming off a career season where he was worth 5.5 fWAR for the Marlins and Athletics, Marte was far and away the best center fielder available in free agency, and the Mets eagerly brought him in to fill a longstanding hole in the outfield.

Marte likely needs little introduction. He started his career with the Pirates and signed multiple below market rate extensions that prevented him from hitting free agency until this season. He’s been passed around a bit in recent years, heading to the Diamondbacks before the 2020 season, then to the Marlins at the 2020 trade deadline, and finally over to the Athletics in a midseason 2021 trade in exchange for Jesus Luzardo.

Over the last half decade, Marte has been one of the most productive players in baseball. Since 2016, he ranks 9th among outfielders in fWAR, and checks in one spot higher since 2019. He consistently posts offensive lines 10-20% better than league average per Fangraphs, though Baseball Prospectus’s numbers are less fond of his work. It’s an old(er) school profile, with limited walks (2021 aside) and limited over-the-fence power. Instead, Mare relies on spraying ground balls and line drives around the field and letting his speed work for him. His IFH% (infield hit) is a great illustration of this, as Marte consistently runs rate over 10% and has the 12th highest percentage in baseball since 2016.

That skill set helps Marte on the outfield grass as well, where Statcast’s OAA metric has pegged him as a consistently above average defender in center field despite subpar jumps. Oddly, his speed hasn’t played quite as well on the base paths. Excluding his outstanding 2021 season, the last time Marte rated as an elite baserunner was 2016, which was also the last time he stole 47 bases. This isn’t to say he isn’t a plus there, just perhaps not as great as one might expect. On the other hand, perhaps he’s learned how to better harness his physical skills as he’s gained experience.

None of this is to say that Marte is not actually a good ballplayer. Even as a bit of a throwback, his speed-driven profile is good for 3-4 wins annually, with the potential for more based on batted ball luck. However, Marte is also 33-years old, and physical skills can go in a hurry once a player reaches their mid-30s. He’s not lose too much speed yet per Statcast (minor decreases in sprint speed and percentile ranking) and their have been elite basestealers that have held onto that skillset as they age. At the same time, it’s impossible to ignore the risk associated with Marte losing a step or two as he ages. Nearly 30% of his value came on the bases and in the field in 2021, and while there’s no direct way to put a number on it, a great deal of his purely offensive value comes for his speed as well.

As we did when discussing the Mark Canha signing, it’s worth describing the realistic downside risk. Marte is probably a safe bet to contribute in center field for 2022, but beyond next season may need to slide to a corner spot. If he loses a step, perhaps his defense slips to merely average or a tick below, and his baserunning skills decline to more pedestrian levels. Without power or on base skills to fall back on, a good chunk of the on-field value Marte produces could dry up in a hurry.

That said, this still strikes me as a very worthwhile investment. Marte put up 5.5 fWAR in 2021 and roughly 10 wins since 2019 (those numbers are 3.7 and 7.8 by WARP respectively), and the Mets are paying him for roughly eight wins over the life of his deal. If Marte continues to be as great as he’s been in the last couple seasons, he pays that off in year two. If he follows an average-ish aging curve, he’s more a fourth outfielder by years three and four but still generates eight wins comfortably. And even in a world where he falls off a cliff, he’s still a fairly safe bet to deliver in 2022, and the Mets are in a spot where it makes sense to overpay for short term value.

This conclusion surprised me, given that I had Marte as an obvious avoid at the start of free agency. However, given his body of work, the reasonable price of his contract, his fit on the roster, and the lack of associated draft pick compensation, this deal seems like a slam dunk that fans should be thrilled about. As such, it earns an A+.