SAN FRANCISCO — Giants manager Bob Melvin shook up his starting lineup Monday. Now, he’s altering his starting rotation.

Melvin announced prior to Saturday’s game against the Athletics that Jordan Hicks will move into the bullpen and Hayden Birdsong will join the rotation and make his first start of the season on Tuesday.

“We’re just trying to get it right at a particular time,” Melvin said. “Jordan came in last year and signed here as a starter. Came in here this year expecting to be a starter and he was, but we’re just making adjustments … a month-and-a-half into the season. We think it’s potentially going to make us better.”

Hicks, despite throwing six shutout innings in his season debut, has a 6.55 ERA over nine starts with 41 strikeouts in 45 1/3 innings. In his last outing, the 28-year-old went two-plus innings and allowed five earned runs, his shortest — and worst — start of the season.

The surface stats aren’t great, but Melvin said Hicks’ numbers aren’t as bad as they may appear.

Melvin pointed to Hicks’ 3.48 FIP, or fielding independent pitching, which indicates that Hicks has been unlucky despite minimizing walks and home runs. In fact, the difference of 3.07 between Hicks’ ERA and FIP is the highest in all of baseball. Last year, by contrast, Washington’s Patrick Corbin had the largest discrepancy at 1.20. Along with FIP, Hicks has an expected ERA of 3.75.

“If you look at a lot of the internal numbers — FIP and so forth — he’s pitched a lot better than maybe his ERA and some numbers would suggest,” Melvin said. “But at this point, that’s what we’re going to do starting on Tuesday.”

It’s unclear how Melvin will use Hicks out of the bullpen. Hicks has experience as a closer with 33 career saves but Ryan Walker, Tyler Rogers and Camilo Doval constitute Melvin’s typical high-leverage options. Birdsong, by contrast, was a multi-inning reliever in low-to-medium leverage situations.

Melvin said the Giants “haven’t figured out exactly where he’s going to fit” but given Hicks’ experience as both a starter and reliever, he could fill either role depending on the needs of a specific game.

Kyle Harrison, a fellow starter-turned-reliever like Birdsong, was not in consideration for the rotation.

“He was great about it. He really was,” Melvin said of Hicks. “He said, ‘I want our team to win. I want to do whatever I can to help the team win.’ He thought the way he’s pitched is better than his numbers, and I agree with him. But again, we have a lot of quality. We have a lot of good young arms. We have a lot of starters and we’re just trying to get it right for a particular time.”

San Francisco moved Hicks from the rotation to the bullpen last year as well, albeit under different circumstances.

Hicks signed a four-year, $44 million deal with the Giants in January 2024 to join the team as a starter after spending years with the St. Louis Cardinals as a reliever. The right-hander started hot (1.59 ERA in April) but transitioned to the bullpen by late July as the innings added up and fatigue set in.

Birdsong, 23, cracked the Opening Day roster for the first time in his career and took the temporary transition to the bullpen in stride, posting a 2.31 ERA over 23 1/3 innings with 25 strikeouts. Interestingly, Birdsong has the opposite issue as Hicks in that he has a 4.74 FIP.

The right-hander isn’t fully built up for a starter’s workload compared to his rotation mates, but Melvin said it’s reasonable he could throw somewhere in the range of five innings and 75 pitches in his first start of the season. On Wednesday, Birdsong threw a season-high 65 pitches over three innings.

FLORES’ BIG NIGHT

Wilmer Flores joined some pretty good Giants company – and nearly made MLB history – on Friday night with three home runs and eight RBIs in San Francisco’s 9-1 drubbing of the A’s in their first game in the Bay Area since moving from Oakland.

Flores hit a grand slam, a three-run home run and a solo shot — yes, a two-run home run short of a homer cycle. That would have been a first in the majors. A pair of former minor leaguers, Tyrone Horne (in 1998) and Chandler Redmond (2022), accomplished the feat when they were playing Double-A in the St. Louis Cardinals system.