The Orioles selected De Leon's contract from Triple-A Norfolk on Tuesday, Andy Kostka of TheBanner.com reports.
De Leon holds a 4.73 ERA, 1.48 WHIP and 121:53 K:BB over 99 innings between Double-A Chesapeake and Norfolk this season. He was recently shifted to the bullpen at Norfolk but has been shaky, allowing four runs with a 6:6 K:BB over 3.2 innings. However, De Leon has a big arm and could be a weapon in relief for the Orioles if he can find the strike zone.