The Marlins selected Mack's contract from Triple-A Jacksonville on Monday.
Mack earned his first big-league promotion after slashing .244/.388/.378 with three home runs and a 20:22 BB:K in his first 24 contests with Jacksonville. According to Christina De Nicola of MLB.com, Mack is in line to start in Monday's series finale versus the Phillies, and the 23-year-old should be in store for ample playing time while sharing reps at catcher with Liam Hicks. Mack is worth a pickup in two-catcher fantasy leagues where he's still available.