Sean Manaea joining the Mets may not be a Yoshinobu Yamamoto-sized splash, but he could be a useful addition to their pitching staff none the less.
In the Giants’ most recent season, Manaea made some intriguing repertoire changes that will be fascinating to watch in 2024. His fastball velocity increased by several mph after working out at Driveline during the offseason. He began tossing a sweeper, the hip new slider that’s gaining traction in Major League Baseball. Furthermore, if the Mets want to use him as a starter, he has to sharpen his changeup, which is a crucial third pitch.
The key question is, which of those changes will the left-hander carry with him to New York?
These three factors will determine whether or not Manaea can return to his best form for the Mets in the upcoming season.
1) Will he embrace the sweeper?
Ever since Manaea’s contract with the Mets became public, there has been much discussion about how his new sweeper contributed to his success in 2023 and may do so in 2024. And for the most part, that is. But it’s not just that.
It’s true that Manaea added a sweeper in May of last year, which contributed to his success after the Giants moved him to the bullpen. He switched from throwing the traditional, harder-throwing slider with tighter movement to the “sweeper” style, which comes in slower but has a lot of horizontal break.
Furthermore, Manaea’s sweeper pitch was indeed a good one. It broke an average of 12 inches as opposed to the 2 inches he broke on his old slider. Instead of allowing hitters to bat.284 against his regular slider, he held them to a batting average of just.140 against the sweeper. Additionally, he produced a 35% swing-and-miss rate as opposed to a 26% slider rate.
The problem is that Manaea only used his sweeper as a reliever. During his two months as a starter for San Francisco (April, prior to incorporating the sweeper into his repertoire, and September, when the Giants inserted him back into the rotation), he exclusively employed his standard slider.
Here’s Manaea’s slider vs. sweeper usage over the course of the 2023 season:
Manaea began incorporating the sweeper into his repertoire after it was introduced, and by August, he was throwing it a season-high 25% of the time, as opposed to just 4% when he was using sliders. However, the slider returned, and the sweeper vanished when he started playing again.
So will Manaea throw the sweeper if the Mets want him to start in 2024? This is a crucial query. If his strong performance from the previous season can encourage him to maintain it as the main weapon in his arsenal, his sweeper certainly seems like it might be the better pitch. His harder slider can still be effective.
Manaea’s four-seamer and changeup break in similar amounts but in the opposite direction, so it seems like his sweeper and these two weapons would work well together. His four-seamer breaks fifteen inches from left to right, while his changeup fades thirteen inches from right to left. Regardless of his role, Manaea should, at the very least, be throwing the sweeper in tandem with his slider.
2) Can he maintain his velo bump?
Manaea’s velocity was the first thing that stood out about him last season, even before the sweeper entered the picture. He was throwing far more forcefully than he ever had before.
In April, Manaea’s fastball averaged 94.3 mph, which was three full mph faster than his 2022 Padres average of 91.3 mph. He kept most of those improvements throughout the season, and even though his September return to the rotation caused a slight decline (relievers can afford to put more effort into shorter outings), he was still throwing over a tick and a half faster (92.9 mph) than the previous season.
This suggests that Manaea’s velocity gain is genuine, which is encouraging for the Mets. In 2023, at the age of 31, he achieved the highest fastball velocity of his career with a velocity of 93.6 mph.
That added velo, coupled with the good running action Manaea gets on his four-seamer — his 15 inches of run gave him top-five movement above average — made his heater a better pitch than it’s been in a long time. Manaea’s four-seamer was worth +6 runs prevented for the Giants, the highest run value for his primary fastball in a season since 2019. In 2022, his four-seamer had a -3 run value.
3) Is his changeup for real?
Whether he is in the starting rotation or the bullpen, Manaea depends on his changeup to attack right-handed hitters, but as a starter, it is especially crucial that he use it as a third pitch. Last season, he used changeups most frequently in April (23%) and September (24%), but when he was pitching in relief, his sweeper was used more frequently.
That implies that if Manaea is in the Mets rotation, they should be expecting him to continue using his changeup. The good news is that last season’s version of his changeup was much better. In contrast to a -10 run value in 2022—when it was among the worst changeups in baseball—Manaea generated a +4 run value in 2023 on that offering, which is well above average.
Why did it get so much better? Initially, it appeared that his fastball’s superior velocity differential was the main factor. In April, Manaea’s fastball velocity was 94.3 mph, while his changeup velocity was 85.8 mph. This meant that in 2022, the difference in velocity between the two pitches was only 6.4 mph.
Even though the velo differential was much smaller at the end of the season (just 5.8 mph in September, with his four-seamer sitting at 92.9 mph and his changeup at 87.1 mph), his changeup was still effective.
Manaea’s ability to induce strong drops with his changeup even when he was throwing it harder seems to be the key in the closing moments of the game. For instance, Manaea’s changeup averaged 84.9 mph with a 31-inch drop in 2022. Even in 2023, when he was averaging a much faster 86.6 mph, his changeup still had an average drop of 31 inches. His changeup went from being below average to above average as a result.
Manaea appears to be a pitcher who is still developing based on his 2023 campaign. The Mets will have scored a steal if he builds on his success and plays out his contract through 2024.