Phillips will begin the season as part of the Marlins' bullpen, Christina De Nicola of MLB.com reports.
The 28-year-old righty produced a 1.13 ERA and 9:5 K:BB in eight innings this spring to secure his spot. Phillips figures to fill a middle-relief role after posting a 2.78 ERA, 1.15 WHIP and 52:24 K:BB over 77.2 innings last season with two wins, four saves and eight holds in 54 appearances for Miami.