A’s Designate Jack O’Loughlin For Assignment

The A’s placed righty Ross Stripling on the 15-day injured list with a lower back strain and selected the contract of lefty Kyle Muller from Triple-A Las Vegas in his place, the team announced. In a corresponding move, left-hander Jack O’Loughlin was designated for assignment.

O’Loughlin, 24, made his big league debut with the A’s this year. The Aussie-born southpaw pitched 9 2/3 innings out of the Oakland bullpen and yielded five runs on 13 hits and five walks with six strikeouts in his first look in the majors. That came on the heels of a 6.19 earned run average through 68 1/3 innings (10 starts, 28 relief outings) in a hitter-friendly Pacific Coast League setting where O’Loughlin fanned 22.9% of his opponents against a 10% walk rate.

It’s the first season in the A’s organization for O’Loughlin, who was originally signed by the Tigers and inked a minor league deal with Oakland over the winter. He fared better in 2023 in Detroit’s system, when he pitched a combined 124 innings of 3.99 ERA ball as a starter between the High-A and Triple-A levels.

Muller, 26, will get a second look with the A’s after being passed through waivers earlier in the season. Once a top prospect with the Braves, he came to the Oakland organization as part of the trade sending Matt Olson to Atlanta. The Athletics hoped to be getting a largely MLB-ready piece for the back of their rotation, but Muller struggled badly in parts of two seasons with the big league club, serving up a 6.39 ERA in 119 2/3 innings of work. The A’s tried him exclusively out of the ’pen earlier this year, and he did turn in a 4.22 ERA more than three runs lower than last year’s 7.60 mark, but Muller’s fastball sat at a career-low 92.5 mph even in spite of the move to short relief, which likely turned some clubs off.

Since going back to Triple-A, Muller has stretched out and moved back into a rotation role. He currently has a 4.76 ERA in 28 1/3 innings. His last appearance was his best yet, as he pitched seven innings and held the Rangers’ Triple-A club to three runs on five hits and a walk with six punchouts. The A’s could use Muller in a variety of ways, and if he can impress over the final weeks of the year, perhaps he can put himself back in position to stay on the 40-man roster and be an option for next year’s staff in some capacity.