Manning, 29, is an intriguing pitcher with some clear strengths and weaknesses. As a rookie with Washington in 2008, he struck out 37 batters in 42 innings and held left-handed hitters to a .203 batting average and .284 on-base percentage.
On the flipside, though, he issued 31 walks and allowed eight home runs, and right-handed hitters managed a .414 OBP while slugging .468 against him.
Though Manning was added to the 40-man roster, he is not guaranteed a spot on the active roster. Rather, he is expected to compete for a spot in the bullpen next season. Other lefties who may figure in that mix are Randy Flores, Tyler Johnson and conceivably Ron Villone, if he re-signs.
Left-handed relief was a significant problem for the 2008 Cardinals. Flores struggled with injuries and ineffectiveness, Villone was sometimes effective but not consistently so, and Johnson missed the entire season with a shoulder injury. It is likely that the Cardinals are still seeking a more prominent southpaw to add to the '09 bullpen.
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.