it woulda all depended on how he approached the MMA game, if he had the mark coleman/kevin randleman/brock lesner type of mindset that all they r gonna do is rely on ground n pound n not work super hard on submissions n submission defense as well as striking n striking defense he will fail, wrestlers that became champions where the ones that realized wrestling just wasnt enough n worked on all the other areas as well. dont get me wrong,wrestling is the best base imo for MMA,but to rely on it alone is foolish, couture,hughes,ortiz,sherk ect all bacame very good at bjj and striking and that helped them bigtime. if karelin woulda trained under a great camp like extreme couture or jacksons or american top team ect he woulda been a top contender imo, but there are so many factors to consider, questions like can he take a punch? or can he learn to fight off his back ect,its hard to say unless he actually fought,but i think he woulda did fine tho