Giants Promote Caleb Kilian to Closer After Troubled Bullpen Struggles

The San Francisco Giants have officially named Caleb Kilian their closer, manager Tony Vitello announced before Thursday’s game against the Chicago Cubs. The decision marks a shift from the team’s committee approach to a more defined bullpen strategy after months of inconsistency.

The Giants entered the 2025 season with one of the top relief groups in baseball but made almost no significant moves over the winter to shore up the back end. A midseason trade sent Camilo Doval and Tyler Rogers to other teams, and then Randy Rodríguez, who was in the midst of a breakout All-Star season, suffered a season-ending Tommy John surgery in September. With a glaring need for stability in the ninth inning, the Giants opted for a patchwork solution, claiming Reiver Sanmartin off waivers and adding rehabbing arms like Jason Foley, Rowan Wick, and Sam Hentges for minimal cost.

Kilian, acquired on a minor league deal, has emerged as the most reliable option. The 29-year-old righty has posted a 3.34 ERA and 26% strikeout rate in 29 2/3 innings this season. His average fastball velocity has climbed to 96.7 mph, up from 93-94 mph during his time with the Cubs. Kilian has already picked up four saves in 2025, including three in June after a rough May that included a five-run ninth-inning meltdown at Coors Field.

The Giants’ bullpen ERA has plummeted since the start of May, ranking among the worst in the league at 5.35. That has forced a more structured approach. Alongside Kilian, the Giants will use high-leverage arms like Keaton Winn and Erik Miller in the seventh and eighth innings. Ryan Walker, who had three saves in April, was recalled from the minors on Thursday. Walker, who allowed 12 runs in 15 1/3 innings this season, hopes to regain a late-inning role.

Kilian was traded to the Cubs in the Kris Bryant deal in 2022 and struggled in limited MLB appearances over the next two seasons. He spent most of 2024 on the injured list but has shown marked improvement in 2025. His performance has earned the trust of the Giants’ coaching staff, who now plan to use him as their primary closer.

The Giants and Cubs meet again Friday at Oracle Park. San Francisco will look to stabilize their playoff hopes with a defined bullpen and a newly assigned closer.