Nathan Eovaldi’s cutter changed everything

The Red Sox, in case you missed it, made their biggest splash of the offseason to date when they brought back postseason hero Nathan Eovaldi on a four-year deal worth $68 million. It was a big move for the team, as it rounded out their 2019 rotation and gave them one more starting pitcher under control for more than a year as they continue to plan for potentially moving into a post-Chris Sale era after this coming season. As we discussed later in the day, it was mostly a good signing from our perspective. There are a few ways this can go south, but that’s true of every free agent contract. A lot of the positives we’ve discussed, while totally valid, have to do with just being happy as a fan. There’s certainly nothing wrong with that, but we haven’t spent a ton of time talking about what this actually means on the field. Is Eovaldi actually as good as we saw for the second half of the season and into October?

Well, he’s not going to be the guy we saw in October over the course of an entire season. I’m pretty confident taking that stance. On the other hand, there is this idea I have seen (largely from national baseball fans more than Red Sox fans) that he simply turned it on in October and the team paid for one good month of baseball. That’s just not true at all, as Eovaldi looked good over the entire 2018 season and was very impressive for his entire three-month tenure with the Red Sox. Now, that’s not to say there aren’t concerns. We’re still talking about one good year that was only 111 regular season innings. It’s not unfair to think it may have been a flash in the pan. There’s plenty of reason to think it was sustainable, though, and it all comes down to the cut fastball.

The cutter wasn’t a brand new addition to Eovaldi’s repertoire or a pitch he just learned to help him take his game to the next level. He used to throw the offering way back in his Dodgers days at the very start of his career, but when he was sent to Miami they had him scrap it. Instead, the Marlins asked him to focus on his slider and changeup, and eventually he started leaning on a splitter. The Yankees then stuck with that repertoire, though he did start throwing the cutter a little bit again in 2016 before getting hurt and eventually undergoing Tommy John surgery.

Then, he signed with the Rays in 2017 as he rehabbed, and while he was coming back for the 2018 season the coaching staff in Tampa suggested he bring the pitch back all the way. It pains me to give credit to the Rays, but they deserve all of it here. Eovaldi started throwing the pitch when he came back in May of this past season, and it absolutely changed everything. He looked like a totally different pitcher, and suddenly his numbers were starting to match the stuff he’s flashed throughout his career.

Photo by Mike Stobe/Getty Images

The results were astounding. Eovaldi had a legitimate standout season in 2018 between Tampa Bay and Boston. Not even including the postseason, he tossed 111 innings over 22 appearances (21 starts) and finished the year with a 3.81 ERA. That ERA doesn’t look great, though it was 12 percent better than league-average after adjusting for park effects. Furthermore, the peripheral numbers were even better. He ended the year with a 3.63 FIP and a 3.23 DRA thanks to pinpoint control and a career-high 8.2 strikeouts per nine innings.

For a long time, Eovaldi had the Joe Kelly issue where his velocity was superb but he couldn’t get the strikeout totals to match it. Like Kelly, he was throwing too many flat fastballs, and major-league hitters are going to hit that regardless of velocity. Then, he added the cutter and added some movement to his repertoire. The results speak for themselves.

Looking at Brooks Baseball, you can see that his cutter quickly became the focal point of his repertoire and opponents really had no chance on the pitch. He didn’t throw the pitch quite as often as his four-seam fastball, but it was close with the fastball being used 40 percent of the time and the cutter coming in at a 32 percent usage rate. For reference, prior to 2018 he had generally thrown that 100 mph fastball about half of the time and he’s used it as often as 71 (!) percent of the time in 2013. The cutter made him more unpredictable, and opponents never adjusted. The pitch ended the year with the lowest rate of called balls of any in his repertoire — a big reason for his 1.6 walks per nine innings in 2018 — but not because of location. Instead, hitters couldn’t lay off Eovaldi’s cutter out of the zone. It was just nasty.

What’s perhaps even better than the results is the confidence Eovaldi clearly has in his new/old pitch. Back in August, the righty spoke to Fangraphs’ David Laurila about the cutter, and the whole interview is worth reading. What stood out to me is the way he talked about why he had confidence in the pitch. Eovaldi is obviously a high-velocity pitcher and has always worked on his fastball. Other pitches never really took, but he says the cutter has because it’s so close to his fastball. It still has the velocity — he throws it up to 96 mph — so he knows if it misses it will still be hard to pitch. With his changeup, as the example he gives, any mistake is basically a batting practice fastball. I thought that was an interesting insight into his game.

Anyway, the cutter is filthy, and we should take a second to appreciate it.

Good lord.

Anything can happen in baseball from year-to-year, and there’s never going to be a guarantee that anyone but the best of the best will be consistently great through a season. That being said, there shouldn’t be major concern that Eovaldi is going to be a one-hit wonder. He’s only entering his age-29 season, and he transformed himself in 2018 with one of the nastier pitches in baseball. That cutter took him from being a guy with velocity and not much else to a legitimate major-league pitcher, and the Red Sox rotation should benefit from him all year long. Now I can’t wait until spring training so I can watch that cutter again.