The component fight sports of Mixed Martial Arts are well established: Folkstyle, freestyle, or greco wrestling, BJJ, and Muay Thai or Boxing. There are Judo, Sambo, or karate based fighters, but they are few in number in comparison.
Josh Barnett is an exception, as his base is pro wrestling. While the idea might cause the uninitiated to laugh, consider that debatably the greatest fighter of all time, Kazushi Sakuraba, also had as his base 'Puroresu'.
Barnett's boast is not pro westling inspired "mic work." He won the IBJJF World No Gi Jiu-Jitsu Championship in 2011.
"I’m the best grappler out there in MMA," Barnett said. "Especially the heavyweight division. But you know, it’s not about talking about it, it’s about being about it, so I’ll just go out there and continue to prove such a thing. Back my words up."
[video=youtube;UeT21dfGZgw]http://www.youtube.com/watch?feature=player_embedded&v=UeT21dfGZgw[/video]