The Pirates designated Ryan for assignment Monday, Alex Stumpf of MLB.com reports.
Ryan will lose his spot on the 40-man roster for the second time in three weeks as part of a flurry of roster moves by Pittsburgh on Monday. The 29-year-old appeared in two games during this stint in the majors, allowing three runs across 3.2 innings. He has a 5.66 ERA in 20.2 innings for Pittsburgh this season.