 Thomas was a contestant on The Ultimate Fighter 4 where he defeated Mikey Burnett in the first round, before losing to training partner Chris Lytle by decision in the semi-finals.Thomas returned at the finale on November 11, 2006, to face Rich Clementi, winning via rear naked choke in the second round.Thomas was then defeated via submission (rear naked choke) by future UFC lightweight title challenger Kenny Florian after injuring his knee in a takedown attempt while headlining the main event at UFC Fight Night 11.