The Cardinals selected Graceffo's contract from Triple-A Memphis on Friday.
Graceffo has posted a 3.84 ERA, 1.35 WHIP and 70:29 K:BB across 75 frames with Memphis this season. All 14 of his appearances have been starts, and while it's possible he'll get a look in the rotation eventually with the Cardinals, the plan for now is to break him in as a reliever. Graceffo will be making his major-league debut when he gets into a game.