With Jaime Garcia likely out for the rest of the postseason with an injury to his rotator cuff, the St. Louis Cardinals added Shelby Miller to their postseason roster on Tuesday:

Cardinals LHP Jaime Garcia (rotator cuff strain and inflammation) removed from #postseason roster and replaced by RHP Shelby Miller.

— MLB (@MLB) October 9, 2012

Miller, a 21-year old righthander considered one of the best prospects in baseball, has pitched well in limited opportunities in the majors this season.

In 13.2 innings, he has a 1.32 ERA while striking out 16 and walking only four. Expectations were sky high for the 6'3, 195-pound Miller coming into the season, but he struggled a bit in the minors as the Cardinals waited for him to find his footing before bringing him up to the big leagues.

Miller will likely be slotted into a bullpen role, where he could be a valuable weapon for Mike Matheny as the Cardinals go back to Washington tied 1-1 with the Nationals in the NLDS.