Giants reliever Reyes Moronta achieved a significant milestone on Saturday at T-Mobile Park in Seattle, where he returned to a Major League mound for the first time since undergoing surgery to repair a torn labrum in his right shoulder in September 2019.

The outing marked the completion of perhaps the most arduous phase of Moronta’s comeback, but he acknowledged that there are still mental barriers to overcome before he’ll be back to fully feeling like himself again.

Moronta’s fastball has averaged 94.2 mph over his first two outings of the season, down from 97.2 mph in 2019, and he admitted that he’s still hesitant to let loose out of fear of reinjuring his arm.

“I need to have a little bit more confidence in myself,” Moronta said in Spanish on Tuesday. “I need to let go of the fear, because I’m still afraid that I’ll get hurt again. When you’re coming off a surgery, sometimes you’re still a little worried and scared.”

Moronta, 28, said he believes his velocity will gradually tick back up as he continues to build up his arm strength and log more innings on the mound. He surrendered a solo shot to Mitch Haniger in his 2021 debut against the Mariners on Saturday, but he came back to pitch a 1-2-3 seventh inning in Monday’s 3-2 win over the Padres at Petco Park.

Even with diminished velocity, Moronta has managed to stay effective by throwing fewer fastballs and leaning more heavily on his slider, which he used to induce three groundouts from Manny Machado, Eric Hosmer and Tommy Pham.

“I’m getting the slider back, little by little,” Moronta said. “It wasn’t breaking as much as before, but I felt like it was better yesterday and closer to how it was in the past.”

Moronta is one of only three right-handed relievers in San Francisco’s eight-man bullpen, and the Giants are hoping he’ll be able to re-establish himself as a key back-end arm as he begins to get more comfortable and gradually move past his injury fears.

“I think every time he goes back out there, he’s going to get more and more confident,” manager Gabe Kapler said. “In the meantime, he can utilize a really nice offspeed mix like he did last night. We saw the changeup come out. The slider has been an especially effective pitch for Reyes throughout his career when his stuff has been especially crisp, and sometimes even when his fastball velocity hasn’t been where he’s wanted it to be.

“Having experienced significant injuries myself, the more you’re out there -- the more you’re on the mound, in Reyes’ case -- the more likely it is that you’re going to have that boost of confidence at the right time. Sometimes, it takes a little bit longer than we expect.”

Yaz returns, La Stella scratched
Right fielder Mike Yastrzemski was scratched from Monday night’s lineup with left hand soreness, but he was cleared to start against Padres right-hander Yu Darvish on Tuesday. Yastrzemski was struck on the left hand by a pitch from A’s left-hander Sean Manaea on the final day of Spring Training and experienced some swelling prior to Monday’s game, but he showed that the injury isn’t too serious by coming off the bench to crush a game-winning, pinch-hit home run in the seventh inning.

Tommy La Stella was expected to start at second base and bat leadoff against Darvish on Tuesday, but he was scratched from the Giants’ lineup with upper back tightness. Wilmer Flores started at second in La Stella’s place.