The Athletics are set to designate right-hander Aaron Brooks for assignment, Martin Gallegos of MLB.com was first to indicate (Twitter link). His 25-man roster spot will go to closer Blake Treinen, who’s set to return from a short stay on the injured list.

Brooks has been a regular for the A’s pitching staff this season, having amassed 50 1/3 innings in 15 appearances (six starts). However, the results have been underwhelming. Brooks has only managed a 5.01 ERA/5.67 FIP, in part because he has surrendered home runs on 19.4 percent of fly balls. On the other hand, the 29-year-old has logged decent overall strikeout and walk rates (7.69 K/9, 2.5 BB/9) and racked up almost a K per inning as a reliever.