Why? Heisey and Frazier have nearly identical OPS numbers from the minors. Both are utility fielders, but Heisey is a better defender. Not sure why Heisey would be the guy.
Because Heisey needs to go down and play every day for a couple of weeks while Ludwick plays himself into a starting role or off the roster in the majors. Walt can get busy trying to make a move to fix the roster. By Memorial Day, Heisey is either:
1. dealt for a Lefty bat who replaces Harris,
2. called up to replace some one else who is dealt for a lefty bat (Frazier?) who replaces Harris
3. called up to replace Ludwick who is cut loose if he doesn't grab the job
4. called back up to replace somebody else who may be injured or deserving of a trip to AAA or DFAville.
Right now I'd like to see him get a couple weeks worth of PAs on a regular basis. It may just be postponing the decision, but it would be useful and would allow the team to try to get a guy going who can't seem to get on any kind of roll with the strange roster configuration that leaves the team with a lopsided offense, a wierd LF rotation and Willie Harris taking up space because the team just doesn't have a decent LH option.