The Orioles activated O'Neill (wrist) from the 10-day injured list Friday.
O'Neill missed the last five-plus weeks with right wrist inflammation but is ready to go after playing three rehab games and homering in his final rehab contest Wednesday at Triple-A Norfolk. Jeremiah Jackson has played well in right field in O'Neill's stead and could become the Orioles' regular third baseman now that O'Neill is back in the fold.