What will A's rotation look like in 2025?

The A's had 13 pitchers start a game for them in 2024, from rookies Brady Basso and J.T. Ginn to the workhorse of the rotation, JP Sears. Only three of those pitchers collected over 20 starts, with Sears leading the way, starting 32 games for a second consecutive year, followed by Joey Estes and Mitch Spence, who each made 24 starts of their own.

Those three starters seem fairly locked into a spot in the A's rotation, though nothing is necessarily certain behind Sears.

Mitch Spence

Spence, a Rule 5 draftee, joined the rotation in mid-May after beginning the season as one of the team's long relief options. In his 24 starts he racked up a 4.64 ERA with a 1.44 WHIP. After the All Star break he made 13 starts and held a 4.37 ERA.

Spence was a solid pitcher for the A's in his rookie campaign, and will likely slot into the rotation as a fourth or fifth option for manager Mark Kotsay.

Joey Estes

Estes, who just turned 23 a week ago, had a bit of an up-and-down season, finishing with a 5.01 ERA across his 24 starts with a 1.23 WHIP. That said, he had some terrific outings, such as the Maddux he threw against the Los Angeles Angels in July, that showed just what he's capable of. He finished with an ERA of 3.03 in August, then just didn't finish strong in September, which upped his season stats across the board. He entered the final month with a solid 4.29 ERA, but an 8.71 ERA for the month had him finish above five on the year.

Estes doesn't have overpowering stuff, but he spots his pitches well, and that has been the key to his success so far. With a full season under his belt, he'll have more experience to draw upon during the offseason in preparation for 2025.

Osvaldo Bido

Bido, 28, was an offseason acquisition that started the year down in Triple-A, but he eventually earned his spot in the rotation and made the most of it. In nine starts, Bido held a 4.14 ERA in 45 2/3 innings, holding a 1.07 ERA. He had a stretch in August where he gave up just 14 hits in 29 innings of work, giving up over three hits just once in five tries. He finished that month with a 1.55 ERA and a 0.79 WHIP.

While it's not much to go on, that dominant period was pretty impressive, and his overall 3.41 ERA (3.36 FIP) should earn him some sort of a role on the Opening Day roster.

5th Starter

This role could go to a few different guys that had impressive stints in 2024. The trio of Hogan Harris, Brady Basso and J.T. Ginn all showed flashes of why this spot could go to them, but only one of them will likely make the rotation. There could be a spot for one of the other two in the bullpen, while the other option stays stretched out in the minors, ready for their own opportunity.

Harris, 27, had the best stat line overall and has the most experience of the bunch, posting a 2.86 ERA across 21 appearances (nine starts), though his FIP was a bit higher at 4.23. He finished the season with a 1.35 WHIP, and his ERA was aided a little by one of the highest left-on-base percentages (78.9%) of his career.

Ginn, 25, made the last start in Oakland A's history at the Coliseum in the sixth start of his MLB career. In those six starts, he held a 4.45 ERA with a 1.32 WHIP, but one thing that he did in 2024 that could endear him to the coaching staff is that he didn't allow too many walks, finishing with a 6.3% rate. Limiting the free passes has been an emphasis for the coaches the past two seasons, and in '24, the staff showed progress on that front.

Basso, 27, is a lefty like Harris, which could be a determining factor in the race during camp, with Sears the only other projected southpaw at the moment. In his four starts, Basso walked just 5.4% of hitters and held a 4.03 ERA with a 1.25 WHIP. Who lands a spot could ultimately come down to who has the best spring

Looming Wild Card

Over the course of the full season, all of the players mentioned above will likely get a turn in the rotation at some point, given that injuries occur. Speaking of injuries, Ken Waldichuk missed the entirety of the 2024 campaign, and should be ready to go by midseason.

Waldichuk was the centerpiece of the Frankie Montas deal with the New York Yankees, and, like many of those mentioned today, has shown flashes of what he can do on the mound. In 29 career starts he has a 5.28 ERA. With the lefty coming off an injury, it's unclear if he'll be added right back to the rotation, or if the A's will have him rack up some innings in the bullpen and build up next winter for a spot in the starting five.