The Rays selected Montgomery's contract from Triple-A Durham on Thursday, Tricia Whitaker of Bally Sports Sun reports.
Montgomery has taken off since moving to the bullpen full-time at Durham last month, turning in 9.2 scoreless innings with a 20:5 K:BB. The left-hander could eventually work his way into high-leverage situations but should work in middle relief initially. Montgomery will be making his major-league debut when/if he gets into a game.