It would make sense for the UFC sure, but why would either fighter want to risk a loss against an opponent they've not prepared for and aren't being offered a decent financial incentive for? Supposedly, as posted above, they wouldn't pay Pettis enough for him to think it was worth taking the main event, he's certainly not going to take even less to be on the mid card with nothing to gain.
Looking at their latest few videos it's remarkable how much production value there is for a completely 'random' attack. Bizarre.