The Cardinals activated Fernandez (back) from the 15-day injured list Tuesday, Derrick Goold of the St. Louis Post-Dispatch reports.
Fernandez has been shelved for all of June due to with lower-back pain, but he's ready to go after making four rehab appearances with Triple-A Memphis. The righty reliever has been terrific in his brief time with the Cardinals this season, putting up a 1.86 ERA and 17:5 K:BB over 9.2 frames.