Peguero, Sanmartin injuries give Giants more questions in bullpen

SCOTTSDALE, Ariz. -- The Giants’ bullpen competition is suddenly looking as wide open as ever.

Roster hopefuls Joel Peguero (left hamstring strain) and Reiver Sanmartin (right hip flexor pain) both suffered recent setbacks that could make them questionable for Opening Day on March 25, creating more questions about how the Giants will assemble their relief mix in the coming weeks.

Peguero, who experienced tightness in his left hamstring at the beginning of camp, threw a live bullpen session without issue and was trending toward pitching in his first Cactus League game this week. But the 28-year-old right-hander ended up re-injuring his hamstring on Monday and was diagnosed with a Grade 2 strain after undergoing an MRI exam.

“I know it's going to be a couple weeks where he's got to get that taken care of,” manager Tony Vitello said Wednesday ahead of the Giants’ game against the Mariners. “It's one of those things that will re-occur if you push it too much, too early. … It’s going to be certainly more time in that case than the other one before he can get out there again. My hope is once that part is good, it's not like you’ve got to wait too long for him to build up his arm strength, because it's a lower-body injury.”

Sanmartin, 29, left Giants camp to join Team Colombia for the World Baseball Classic on Sunday, but he returned to Scottsdale Stadium on Wednesday after hurting his hip while fielding a comebacker in an exhibition game against the Pirates in Bradenton, Fla., on Tuesday. The veteran left-hander was evaluated by team orthopedist Ken Akizuki on Wednesday and is not expected to rejoin Colombia for the WBC.

“I think the WBC is a wash for him,” Vitello said. “I haven't spoken to him directly about that. I'm sure he's a little bit disheartened or heartbroken about that piece of it. But fortunately, there's still time. It's not early in camp, but it's early enough on the calendar that he can get through a little bit of rest on that deal. It's never ideal where you miss any time, but his arm is something that he can still keep active between now and then, in minimal fashion. But hopefully that'll make things go a little quicker once this lower half is where it needs to be.”

Sanmartin is the Giants’ third left-handed reliever to be sidelined this spring; Erik Miller (lower back tightness) and Sam Hentges (left shoulder surgery) have also yet to appear in a Cactus League game due to injuries. Miller threw a bullpen session on Wednesday and could pitch in a game next week, but Hentges is still building his arm back up from his left shoulder capsule and labrum repair in September 2024.

That leaves Matt Gage and non-roster invitees Juan Sánchez and Nick Margevicius as the only healthy left-handed relievers in Giants camp right now. Gage gave up five runs (one earned) over two-thirds of an inning in the Giants’ 15-1 exhibition loss to Team USA on Tuesday, but he emerged as a bullpen contributor in 2025, when he logged a 3.19 ERA over 27 appearances for San Francisco. The 33-year-old is out of options, so he’s a solid bet to earn a spot in the Opening Day bullpen this year.

Vitello also said “expectations have been exceeded” by the 25-year-old Sánchez, who is coming off Tommy John surgery and has worked 2 1/3 scoreless innings in his first three Cactus League appearances.

Ryan Walker, JT Brubaker, Jose Buttó and Spencer Bivens are projected to be part of the 2026 relief mix, but the Giants are still trying to figure out how to round out the rest of the ‘pen. Non-roster invitees Caleb Kilian and Gregory Santos have both flashed intriguing stuff on the mound, so they could be well-positioned to make a push for some of those open bullpen spots this spring.

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“The competition piece is still high there, so it might provide an opportunity for somebody that wasn't normally going to get one,” Vitello said. “And then you end up with more depth than you would before.”

Worth noting
Walker and right-hander Hayden Birdsong both pitched in a simulated game at the Giants’ player development center at Papago Park on Wednesday. Walker threw 23 pitches over one inning, while Birdsong got up to 39 pitches over two innings.