5. Chris Leben UFC 168
Ever since he appeared on the 1st season of the Ultimate Fighter Chris Leben was a household name in the UFC. While he never was a serious contender in the middleweight division you could always count on Leben to have a good fight. By the time this fight rolled around however Leben was tailspinning, having lost 3 in a row.
His opponent that night, Uriah Hall, was just too much for him and Leben wouldn’t come out for the 2nd round, or ever again. Although he initially retired after this fight Bellator made Leben an offer to come back and fight for them, which he accepted. Pre-fight medical tests discovered Leben’s heart to be in bad condition however, and doctors declared his career over.
