Well a Champion that had a 90 day training camp should certainly not be allowed to pull out of the fight due to his opponent getting injured. The opponent stepping up is the one who is "Actually" stepping up on short notice. That should have been a rule since day 1. I hope they make headliners sign contracts from now on that state you are "agreeing to fight on this date" instead of "you are agreeing to fight this opponent".
An injury or something else horrible should be the only reason a champion is allowed to pull out.
Wanting 3 more weeks to prepare after having 90 days... is not a good reason.