Sledge is worth a shot in deep leagues as a platoon player. He's an okay across the board type, nothing sensational. Figure .270, 10-15 HR, similar steals. He'll likely sit vs. most lefties, so only take him if you have roster flexibility to use him in a like fashion.
Side note...as usual, Sporting News is pretty much clueless. Sledge is not close to being the best prospect in the Montreal organization. He's already 27, and it's also important to note that he was one of the guys who tested positive for steroids during the Team USA tryouts last October. There are at least a half dozen Expos prospects with much higher ceilings.