Wells underwent successful core-muscle surgery Thursday, Roch Kubatko of MASNSports.com reports.
Wells landed on the 7-day injured list at Triple-A Norfolk last week, and a decision to have him undergo surgery was subsequently made. It's unclear how long his rehab will take, but Wells almost surely won't be an option for the Orioles before the All-Star break. He holds a 4.50 ERA, 1.36 WHIP and 36:11 K:BB across 36 innings at Norfolk this season.