The Marlins recalled Blalock from Triple-A Jacksonville on Tuesday.
Blalock was acquired from the Rockies in a trade back in January but has spent all season at Jacksonville, posting a 5.61 ERA and 103:46 K:BB over 109 frames covering 23 starts. The right-hander appears set to be deployed in long relief, though he could wind up making a start or two during the final month.