PHILADELPHIA — Sometimes transactions are pretty self-explanatory: The San Francisco Giants don’t have an off-day until the middle of the next homestand, Blade Tidwell threw 47 pitches on Tuesday night, the team needed a fresh arm and Gregory Santos was thriving at Triple-A Sacramento. 

And yet there might be a bit more going on. Manager Tony Vitello said that Tidwell is getting stretched back out to start at Triple-A Sacramento, and he also mentioned that Carson Whisenhunt had a strong outing for the River Cats on Tuesday night. The Giants might need a spot starter May 4 at San Diego given Wednesday evening’s postponement — and the team does have one pitcher who’s struggling significantly, Adrian Houser, who’s one of the scheduled starters Thursday. Having a starter or two ready to go at Sacramento for any reason, though, is an excellent plan.  

Santos, 25, was with the Giants organization from 2017-22, making his big-league debut in 2021 and pitched in three games, but he was sent down in late April and two months later was suspended after testing positive for performance enhancing substances. He was traded to the White Sox in December 2022 when the team signed Sean Manaea. 

He appeared in 60 games with the White Sox in 2023, then eight in each of the past two seasons with Seattle, but injuries sidelined him much of those two years, and in December, he re-signed with the Giants as a minor-league free agent. He’s been terrific at Sacramento, with a 2.45 ERA and .220 opponent batting average, though two of the three runs he’s allowed came in his last two outings. He last worked Sunday, so he’s plenty fresh.

“I think I’ve been pitching very well, controlling the zone, attacking the hitters, and just creating a lot of contact,” Santos said, with Erwin Higueros interpreting. 

“Obviously, when you have an arm like his, it’s easy just to get in heater mode,” said catcher Eric Haase, who came up from Sacramento last week when Daniel Susac (elbow) went on the injured list. “But I think he did a really good job of mixing up his pitches, and that made his fastball that much more effective. 

“He’s a competitor, man. The persona that he takes on when he’s on the mound, you can tell he’s out there trying to punch people out. It’s great to have when you’re behind the plate, that level of seriousness and whatnot. He’s got purpose and all the confidence.”

To make room for Santos on the 40-man roster, the Giants placed outfielder Jared Oliva (hamate fracture) on the 60-day IL.