Irvin was optioned to Triple-A Norfolk on Thursday, Roch Kubatko of MASNSports.com reports.
Irvin allowed six earned runs across only four innings against the Athletics -- his former team -- Thursday. After three turns through the rotation this season, he carried a 10.66 ERA and a disastrous 5.7 BB/9 and 1.4 HR/9. He'll likely be back in the big-league rotation at some point during the campaign, but he'll have to sort things out in the minors in the meantime. In the short term, the move likely means that both Kyle Bradish (foot) and Grayson Rodriguez will stick in the starting five once Bradish returns from the IL.