The Padres optioned Cosgrove to Triple-A El Paso on Tuesday.
Cosgrove allowed one run on one hit with two strikeouts across one inning in Wednesday's 6-1 win over the Dodgers.
Cosgrove (hamstring) was activated from the 15-day injured list Saturday.
The Padres placed Cosgrove on the 15-day injured list Friday with a left hamstring strain.
The Padres recalled Cosgrove from Triple-A El Paso on Wednesday.
The Padres plan to call up Cosgrove from Triple-A El Paso prior to Wednesday's game against the Cubs, Bob Nightengale of USA Today reports.
The Padres optioned Cosgrove to Triple-A El Paso on Friday.