I hope they do not go the EliteXC way and ask Thompson (or whoever Kimbo's opponent will be) to not kick him or take him down.
Don't forget that Kimbo's knee was a mess (And I don't think that now it is much better. He is older so probably his knee is even worse) and that he has nothing to offer in the ground game.
Plus, I do not think he has been training for MMA since he retired. So now he will still be a brawler with legit KO power. But if he fights against a decent MMA fighter (who will not be scared as hell to face Kimbo), he will be beaten even worse than in the Mitrione fight.
Personally, I don't think they would be able to get away with it after Petrucelli bringing attention to the situation after he raped Kimbo.