Miller, 36, made two All-Star teams and won an ALCS MVP in 2016. After flaming out as a starter, the lefty became one of the most impactful relievers in recent history, both in terms of raw numbers and also how teams viewed reliever usage. In a four-season run from 2014-17, he posted a 1.72 ERA, 0.79 WHIP and 421/67 K/BB ratio over 261 innings. Miller was also revered by his peers for his work with the MLBPA.

Miller went down late last month with a left foot blister, but he's ready to roll for Monday's opener against the Dodgers. The southpaw holds an unimpressive 4.94 ERA over 34 appearances this season. 

Miller has struggled mightily, compiling a calamitous 4.94 ERA, 1.65 WHIP and 31/14 K/BB ratio across 31 innings (34 appearances) this season. It's unclear exactly how long he'll be sidelined.

Miller has been on the injured list for over a month after dealing with a recurring blister on his right big toe. Prior to the injury he struggled with a 6.43 ERA and 2.00 WHIP over 10 appearances. Andrew Webb was designated for assignment by St. Louis in a corresponding move.