The Pirates designated Stratton for assignment Saturday, Danny Demilio of PittsburghBaseballNow.com reports.
Stratton will give up his place on Pittsburgh's 40-man roster to make room for Camilo Doval, who was acquired in a trade with the Yankees on Saturday. Stratton has given up two runs in 3.1 big-league innings this season but hasn't yet allowed a run through eight frames at Triple-A Indianapolis.