10.) Roger Huerta
The once-promising Huerta signed with the UFC in late 2006, winning his debut over Jason Dent and going on to fight a remarkable five times in 2007, winning all of them. His surge saw him as the first-ever MMA fighter to appear on the cover of Sports Illustrated (he’s since been joined by Ronda Rousey), signifying his possible status as one of MMA’s future stars.
But decisions losses to Kenny Florian and Gray Maynard, coupled with a questionable decision to pursue acting in 2009, apparently took away all of Huerta’s considerable momentum. He returned to fighting but lost six of his eight fights since that fateful 2007, and was last seen beating Christian Holley under the ONE FC banner in August 2014. He’s still around, but Huerta could have done so much more in MMA, especially in the UFC.