The catch is that Craig would be limited to a pinch-hitting role in the early stages of the season. If the Cards take such a route, then the fifth outfielder on the roster would need to be capable of playing center, something Craig can't do, particularly in his present, compromised state.
Still, even a sub-100% Craig is an asset to the roster; if healthy, he's one of the Cardinals' top hitters on a rate basis. Manager Mike Matheny, however, is tasked with finding Craig regular ABs in a lineup that already includes Matt Holliday, Carlos Beltran and Lance Berkman at Craig's most familiar positions. There are, of course, worse problems to have.