Mickey Callaway’s days as manager of the Mets seem numbered, and that’s wrong. It’s not his fault the Mets are sliding, and Robinson Cano can’t hustle to first base. GM  Brodie Van Wagenen was praised for his off-season moves, but so far, many of them haven’t panned out. Callaway is the scapegoat, for a team that doesn’t need to push the panic button.