The Oakland Athletics placed left-hander Sean Newcomb on the 15-day injured list on Sunday because of a strained left knee.

The move, retroactive to Saturday, came following his most recent appearance Friday, when he allowed four runs, three walks and five hits, including a home run, in three innings of a home loss to the San Diego Padres.

Newcomb, 30, is 1-1 with a 3.00 ERA, nine walks and 17 strikeouts over 15 innings in seven games since being traded on Aug. 21 from the San Francisco Giants, for whom he appeared in 20 minor league games (two starts) with a 1-1 record and 3.15 ERA in 34 1/3 innings.

In corresponding moves, the A's selected right-hander Joe Boyle from Triple-A Las Vegas and transferred right-hander Freddy Tarnok (right calf strain) from the 15- to the 60-day IL, clearing a spot on the 40-man roster and ending Tarnok's season.

Boyle, 24, a career minor leaguer, was acquired from the Cincinnati Reds on July 31 for left-hander Sam Moll.

Boyle was a fifth-round pick of the Reds in the 2020 MLB June Amateur Draft out of Notre Dame. This season at Double-A and Triple-A affiliates in three leagues, he is a combined 8-8 with a 3.84 ERA, 93 walks and 168 strikeouts in 117 innings over 25 games (all starts). Boyle is 2-1 with a 2.08 ERA with seven walks and 28 strikeouts in 17 innings in three starts at Midland, Oakland's Double-A affiliate.

Tarnok, 24, was 1-1 with a 4.91 ERA over 14 innings in five games (one start) for Oakland this season.