The Pirates recalled Ryan from Triple-A Indianapolis on Sunday.
Ryan will rejoin Pittsburgh's 26-man active roster as a replacement for southpaw Marco Gonzales (forearm), who was placed on the 15-day injured list in a corresponding move. The right-hander reliever has previously made four appearances out of the Pirates bullpen this season, logging a 6.75 ERA and 1.50 WHIP over 5.1 innings.