SF Giants bullpen is reeling, but there is help on the horizon

A handful of relief pitchers will make their start towards recovery this week as the SF Giants bullpen continues to struggle amongst a difficult schedule.

The Giants currently rank 28th in the league in run differential as their bullpen ranks 22nd in ERA. The Giants are putting up a -21 run differential so far this season, with a -22 home split, but a +7 away. For reference the 2025 Giants had a run differential of +21. While the Giants offense is to blame as well for this abhorrent stat, the bullpen has faced a lot of struggles to start the season. The good news is help could be on the way.

3 SF Giants bullpen arms are on their way back to the mound

Joel Peguero

Joel Peguero starts a rehab assignment this week with Triple-A Sacramento. The 28 year old flame-thrower made his MLB debut with the SF Giants in 2025 after spending nearly a decade in the minors.

Peguero managed a 2.42 ERA and allowed 15 hits in 22.1 innings last year. Sidelined in spring training due to a hamstring injury, He will now take a big step in his return with in game reps. Peguero boasts a nasty sinker and four seam both brushing 100 mph, and backs it up with a 91 mph slider. In his limited time in 2025 he also posted a 54% ground ball rate.

While impressive, his ability to induce ground balls actually doesn't help a defense that has been struggling with grounders, with a fielding success rate of 78%, near the bottom of the league. For reference the Atlanta Braves lead the league with an 85% fielding success rate.

With Ryan Walker struggling, and no clear replacement for the closer role, Peguero could make a strong case for himself should he perform well. However he will have to prove he is fully ramped up in Sacramento before making his big league return.

Sam Hentges

Sam Hentges was out all of 2025 after undergoing a shoulder surgery in 2024. Now taking live reps in batting practice, the 29 year old left hander could literally be huge for the SF Giants. Standing at 6-foot-8 and 225 pounds, the innings-eater also boasts elite strikeout stuff. With nearly a 30% strikeout rate in 2024 before suffering a shoulder injury that has kept him out since.

His velocity is backed by solid movement on his pitches, but he has been held back largely by his 8.4% career walk percentage which is around league average. The years in which his walk rate has been below 8% have been his best.

When healthy, Hentges has potential to account for more than 60 innings pitches in a season. It is hard to say if Hentges will be able to return to his former self, but if he can he will be an important asset for the bullpen.

Jason Foley

Jason Foley also started his rehab this week throwing a bullpen. The 30-year-old pitcher is recovering from a right shoulder injury that kept him off the field for the majority of 2025.

Foley mostly relies on his sinker and slider, with lots of velocity behind both pitches.

Foley had been great for the Detroit Tigers in 2023 and 2024 before being sidelined by an injury. He accounted for 24 saves in 2024, good for fifth-best in the American League. that season

While Foley is a still a good ways away from making his debut with the SF Giants, he could be a very solid option for the closer role when he is ready.

The Giants have had a gauntlet schedule so far and it won't ease up until the end of April. They will have to make do with the pieces they have now. At times, they have shown flashes of being a competitive ball club. If the Giants can come out of this month near .500 they could have a real chance to make a push in the second half of the season especially if they get these bullpen arms back.