The Cardinals have added right-hander Trevor Rosenthal to their bullpen. Rosenthal has been a member of Double-A Springfield's rotation all season. The Cardinals do not project him to be a long-term reliever, but with a currently unsettled bullpen, the team needs a boost. St. Louis optioned reliever Maikel Cleto to Triple-A Memphis in order to add Rosenthal to the 25-man roster.