He doesn't Roach saw his defence and decided not to take him on. Said "I've got more chance of toughening Khan's chin than sorting that out" :rofl
Well it was scrapped for the time being, with the possibility of him joining up with Roach for his next fight after Prescott, although that looks unlikely now as Warren seems to be lining him up to fight Khan in the future.
I think he really needs Roach to help him with his footwork, head movement, jabbing more etc Mitchell is good at it but Roach could make him better.
Good luck to Kevin. He's soon to be a father and didn't want to switch to LA. Unless he loses, I doubt he'll leave Tibbs.