"He's been working on a lot of things," A's manager Bob Melvin said. "Getting the ball down, incorporating his other pitches and so forth. He just got a little bit out of sync, but we also know he has quite a track record of pitching well at the big league level. Hopefully this is a start of a nice run for him."
Hahn, originally drafted by the Rays in 2010, was 6-6 with a 3.35 ERA in 16 starts for the A's last year when he suffered a season-ending forearm injury. Healthy entering the year, he was considered to be an integral piece of the A's rotation, but he stumbled in spring and again when the A's promoted him in two separate stints, posting a 6.49 ERA.
Melvin sees this as an opportunity for Hahn to regain his 2015 form.
"He's a guy we felt really confident with on the mound last year," Melvin said. "Every time he took the mound we felt like we had a good chance to win. He had games where he's dominated. He just needs to get on a little bit of a roll, get his confidence back. It'd be a nice addition for us if he can pitch like we feel he is capable of pitching."
Hahn pitched on turn for the Sounds on Wednesday but only went one inning to ensure his availability for Sunday, which would have been Rich Hill's day to go. Hill, who continues to battle a blister, played catch a second consecutive day Thursday, but the A's still don't know when he'll be able to start again.
Jane Lee has covered the A's for MLB.com since 2010. Follow her on Twitter @JaneMLB.