Rowley was optioned to Triple-A Buffalo on Thursday, Arden Zwelling of Sportsnet.ca reports.
Rowley will head back to the minors to clear room on the roster for Thursday's starter, Tom Koehler. Whether Rowley will rejoin the big-league rotation at some later point in the season remains unknown. In three starts for the Blue Jays this season, he's compiled an unimpressive 4.61 ERA and 7:9 K:BB.