Are the SF Giants using Sean Manaea in the right bullpen role?

SF Giants lefty Sean Manaea has pretty much filled every pitching role in 2023. He has been a starter, a reliever, and a bulk innings arm. Most recently, he has been used as a bulk innings pitcher every fifth day, but is that the right role for him?

Are the SF Giants using Sean Manaea in the right bullpen role?

Anthony DeSclafani, Alex Cobb, and Logan Webb have been the primary starters in the rotation. Alex Wood has slotted back into the rotation, so the Giants have four-fifths of a rotation. In essence, Manaea has been the fifth arm despite pitching out of the bullpen.

In an effort to minimize his exposure to right-handed hitters, the Giants have recently used Manaea in a bulk innings role. John Brebbia typically serves as the opener to face off against a lineup that leans in favor of righties at the top. This has worked, but it may not be the optimal use of Manaea's skill set.

The veteran pitcher struggled to the tune of a 7.54 ERA with 28 strikeouts against 14 walks out of the rotation earlier this season. This is on the heels of a rough 2022 campaign in which he registered a 4.96 ERA in 30 appearances, including 28 starts. There is no denying that the rotation just was not a fit for Manaea at this stage in his career.

With an ERA like that, he was just unplayable out of the rotation. And, the Giants have navigated through a year in which the rotation has performed at the extremes. This has been typically good when DeSclafani, Cobb, or Webb start, but it has been rough with Stripling or Manaea on the mound.

A move to the bullpen has undoubtedly paid dividends. The left-handed pitcher has posted a 4.39 ERA with 35 strikeouts against seven walks. His numbers have been better across the board as a reliever. Overall, he has a 5.84 ERA in 15 appearances for the Giants in 2023.

He averages nearly three innings per appearance out of the bullpen. Though, his best production in terms of opponent OPS has typically come at the beginning of his appearances:

Pitches 1-25: .549 OPS

Pitches 26-50: .803 OPS

Pitches 51-75: .868 OPS

The hitter will usually tell you how you are throwing. And, with Manaea, the hitter typically struggles through the first 25 pitches, but improves after that. This is not uncommon with pitchers.

The cause could just be a lack of reliable offerings. Throughout his eight-year career, the lefty has relied on a fastball, slider, and a changeup, The fastball has either been a sinker or, more recently, a four-seam fastball.

The changeup has been effective against righties, whereas the slider has been useful versus lefties. Overall, opposing hitters have recorded a .245 batting average against the slider and a .190 batting average against the changeup. On the other hand, hitters have tallied a .275 batting average and a .484 slugging percentage against the four-seam fastball.

The four-seam fastball is not functional and the slider is more on the fringes of being an option, leaving the changeup as his best pitch currently. Given this, it is no surprise to see that he struggles as the picth count trends upward.

He just does not have an arsenal to mix it up against opposing hitters. They quickly figure out his plan and adjust. This is often the case with relievers. They have one or two pitches that they use in shorter outings. This seems to also be the case with Manaea.

While throwing out of a bulk innings role might be due to need for the Giants, Manaea might be better-suited in more of a one-inning role. The pitching staff is relatively fluid in terms of roles at the moment, so changes will happen as promotions come or when the staff returns to health. When that does happen, it might be best to see Manaea in a different role within the bullpen.