Mets Bolster Rotation, Sign Kodai Senga

Mid-day Sunday in Japan (and typo-inducingly late Saturday night in the U.S.), the New York Mets added to their rotation, signing 29-year-old righty Kodai Senga to a five-year, $75 million deal. The contract reportedly includes a no-trade clause and an opt out after the third year of the contract.

The addition of Senga provides the Mets rotation with perhaps the final hard-throwing patch it needed due to the departure of several free agents. The Flushing starting pitcher carousel has seen Jacob deGrom, Taijuan Walker, and presumably Chris Bassitt depart, while that group has been replaced, seemingly man for man, by living legend Justin Verlander, José Quintana, and now Senga, an 11-year NPB veteran who led Japan’s top league in strikeouts in 2019 and ’20.

After starting his career as a reliever, Senga moved into the Fukuoka Hawks rotation in 2017 and has spent the last half decade as one of the better starters (and hardest-throwing pitchers) in all of Nippon Professional Baseball. As I noted when analyzing Senga for our Top 50 Free Agent ranking (Senga checked in at no. 18), while the soon-to-be 30-year-old righty struggled with walks early in his tenure as a starter (he walked 75 hitters in 180 innings in 2019 and 57 hitters in 121 innings in ’20), free passes have become less of an issue during the last two seasons. Senga’s walk rate has fallen from the 10-11% range to the 8-8.5% range during that stretch, and his WHIP was a measly 1.05.

Senga has also added four ticks to his fastball since debuting in NPB. This wasn’t a gradual increase, either – it happened all at once in 2019. He now sits 96 mph and will touch as high as 102, though he typically tops out at 99 in any given start. Even though premium velocity is rare in Japan, Senga’s fastball doesn’t play like a premium pitch due to some of its underlying traits. He has a relatively upright lower half throughout his delivery and a high three-quarters arm slot that, in combination, create a relatively hittable angle and shape of movement on his fastball. In fact, his dastardly mid-80s splitter, which falls off the table and finishes below the strike zone, is easily his best offering, garnering twice as many swings and misses as his fastball in 2022, and about as many whiffs as the rest of his many pitches combined.

Those pitches (in order of usage) are an upper-80s cutter, a mid-80s slider, and the occasional slower curveball. The slider’s shape and velo sometimes bleeds into the other two, and breaking ball consistency, crispness, and location are sometimes issues for Senga when you dive deep on the tape and isolate those pitches.

There are some scouts and executives who prefer when a Japanese pitcher’s skill set is tailored like this (as opposed to being more reliant on breaking stuff), with the thinking being that the subtle differences in the size and seams of the NPB and MLB baseballs make it tougher to predict how breaking ball quality will translate when changing leagues. Senga’s skill set is driven by fastball velocity, a great splitter, and his demonstrated durability. One could argue that at least two of those attributes are subject to variance of their own due to the forthcoming change in Senga’s pitching schedule, assuming he is part of a standard five-man rotation with the Mets. While Senga has worked at least 120 innings in all but one of the last seven seasons (the lone exception was 2021, when a badly sprained ankle and resulting ligament damage kept him out for a couple months), he did so while pitching every seven or eight days rather than once every five or six.

If for no other reason than he hurls a baseball for a living, there’s risk that Senga won’t pan out, and that risk is perhaps elevated by his recent injury history (he also dealt with two bouts of elbow tightness in 2022, which cost him time in May and July) and the nature of the intense occupational and cultural transition he’s about to make. But if the exciting components of his talent hold water, he’ll be a fitting mid-rotation starter on a contending Mets team.

Even with his opt out, Senga currently has the longest contract among Mets starters. Carlos Carrasco is entering the final year of his deal, Max Scherzer and Quintana are inked for two more, and Verlander might only be on board for two if his third year option either fails to vest or does, but he decides to opt out (it becomes a player option with 140 innings pitched in 2024). Generating pitching depth over the next two years is going to be important for the Mets to fill in behind that group. Of course, they could just continue to plug their holes with free agents as needed.

The $15 million average annual value of Senga’s contract is in line with that assessment, and in a vacuum, it might even be a little below his anticipated $/WAR-based valuation, without the luxury tax or the team’s competitive hopes in mind. (It also constitutes a pretty spot-on projection from our own Ben Clemens and the contract crowdsourcing nerds in our readership.) The Mets blew through the final luxury tax threshold when they re-signed Brandon Nimmo on Thursday, and the addition of Senga puts their base payroll at $335 million, $85 million more than the second place Yankees. If the math done by our own Jon Becker is correct, the Mets are currently set up to pay $414,997,666 in real payroll and tax penalties next season. In my novel and expert opinion, Mets owner Steven Cohen has a lot of money and is willing to spend it to help ensure his baseball team is extremely competitive. Whether his behavior alters that of other owners, who often act as though they’re running a touch-and-go business despite baseball’s obvious profitability, is to be determined. From the point of view of a thousandaire baseball writer who isn’t signing Edwin Díaz’s checks, this is a logical line of play for the Mets to take as they aim to punch back at the last two National League champions, both of which reside in their division.