Even though Orlando's having success on the court, they're one of the teams that tends to get mentioned when discussing franchises facing a lot of financial pressure. If his role is to play 10-15 minutes a game behind Dwight, you just can't pay a guy $5M or $6M a year for that. Battie's on the books for another year, too, so you're really still talking about your third string center, be it Batman or Gorat, making full-MLE $$.
If they wanted to take salary back, I'm sure they could arrange a sign-and-trade and get something decent in return, but I suspect they'll let him walk rather than have to absorb salary.
EDIT: Forgot this would be one of those base-year comp deals. If you're a Magic fan, get your fill of watching Gorat over the next few games, because he's gone.