The Dodgers recalled McDermott from Triple-A Oklahoma City on Saturday.
Acquired in a trade with the Orioles in April, McDermott made a lone appearance out of the Dodgers' bullpen during a prior stint with the big-league club. He has put up ugly ratios in the minors this season but has also struck out 30 batters in just 16.2 innings with Oklahoma City. McDermott replaces Blake Treinen (elbow) on the active roster.