Of course this is MMA and not pro wrestling, but the marketing tactics of both do share some overlap. After watching the first three episodes of TUF 10, it seems as if they UFC is promoting him as the heel. They already knew that Nelson would be fighting Kimbo first so what did they do? They showed Nelson arguing with his coaches, made fun of his physique, said he didn't like to train with others, and portrayed Kimbo as the down to earth humble guy from the streets. They clearly painted Kimbo as the underdog and rightfully so. The casual fan is already familiar with Kimbo anyways, so they would more than likely be rooting for Kimbo to win regardless of what Nelson brought to the table. Which brings me to my next point.
There isn't anything that's really marketable about Roy Nelson. His physique isn't like your typical MMA guy that's shredded and tatted up with ink everywhere. However, the guy can fight and even though the promotion of him on the show thus far has been in a negative light, they haven't done so without letting viewers know that he's a legitimate fighter. I mean how many times have you heard 'former IFL heavyweight champion' in the past 3 weeks? Nelson's the overall favorite to win the show, so it's the job of the UFC to keep this guy fresh in people's minds regardless of if it's good or bad. As long as you know who he is and want to see him either win or lose then it's mission accomplished for the UFC.
The only thing with that though is that he wasn't overly impressive in his fight with Kimbo, and Dana White was already clowning him afterwards. Of course, whatever Dana White thinks, the casual fans will believe. Nelson spoke in an earlier interview about some 'drama' in the house after the fight with Kimbo, so I wonder what that's all about. However, it's clear to me that the UFC is trying to make Nelson stand out somehow, and right now it seems to be as the heel of the show. So I wonder how Nelson will be depicted from here on out? Will the marketing of him on the show help him or hurt him afterwards?