The SF Giants are likely set with the rotation following the reported addition of Tyler Mahle. However, the Giants are still going to have to lean upon their young arms at times in 2026 and Trevor McDonald is one young Giants pitcher no one is talking about.

The Giants rotation in 2026 is most likely going to consist of Logan Webb, Robbie Ray, Landen Roupp, Adrian Houser, and Tyler Mahle. Outside of Webb, all of those pitchers have had trouble making it through a full season healthy.

SF Giants could have hidden gem in Trevor McDonald

The Giants could potentially still add another name into the mix, but with the self-imposed limitations the Giants are operating under it does not seem all that likely that they’d bring in another arm.

The fact that the Giants are so unlikely to get full seasons from all five starters is why young arms like Hayden Birdsong, Carson Whisenhunt, and McDonald are going to be so important.

Birdsong and Whisenhunt come more readily to mind when thinking about young arms the Giants have because Birdsong has seen action each of the last two seasons and has flashed the raw stuff that can play at the big league level. Whisenhunt is the top pitching prospect in the organization so naturally he is going to be thought of when considering the future of the pitching staff.

Yet, McDonald’s name can get lost in the shuffle. The 24-year-old has only seen MLB action at the very end of each of the last two seasons. In 2024 he pitched in the final game of the season and tossed three scoreless inning. He was called up towards the end of the 2025 season and pitched well. In three appearances and two starts, he pitched 15 innings and had a 1.80 ERA with 14 strikeouts and just two walks.

After how well he performed it was fair to wonder why he was not called up sooner especially since the Giants dealt with injuries in the rotation and were relying on the likes of Whisenhunt, Carson Seymour, and Kai-Wei Tent to pick up the slack.

Yet, looking at McDonald’s Triple-A numbers in 2025 one understands why he did not receive the nod sooner. In 29 appearances and 24 starts he had a 5.31 ERA in 142 innings pitched. The Pacific Coast League is notoriously hitter-friendly so those numbers may have been a bit inflated due to that.

But going into 2026, McDonald needs to be considered right alongside Birdsong and Whisenhunt if there is an injury to a member of the rotation or a young arm is needed to eat up innings. He has proven he can be effective at the big league level so maybe he could surprise some people and make himself a part of the rotation in 2026.