There is a former UFC star training at the WWE Performance Center, according to a report by Dave Meltzer of the Wrestling Observer Newsletter.
At this time, we don’t have confirmation on who the fighter is and there is said to be a lot of secrecy around his identity.
The mystery fighter in question is said to have most of the attributes that WWE is looking for, but is older than what WWE looks for in a potential developmental wrestler.
The WWE Performance Center is home to WWE’s talent development system, NXT. The 26,000 square-foot facility opened a year ago and features seven training rings, a world-class strength and conditioning program, as well as cutting-edge edit and production facilities and also a voice-over room for wrestlers to practice their “promo” skills.
Rashad Evans has been rumored to be interested in a WWE career after he retires from MMA and recently told MMA Mania:
“I had a million people asking me if I was retiring for wrestling, but honestly speaking, if I didn’t get seriously paid to do it I wouldn’t do it. I think it would be disrespectful to my legacy in the UFC if I didn’t do a deal that would make sense where I got paid! Besides, that s**t is harder on my body than fighting.”
Another possibility is Chael Sonnen. Sonnen is a longtime WWE fan and is also friends with Brock Lesnar, Paul Heyman and former WWE Superstar CM Punk. While the stench of getting bounced out of MMA due to drugs is probably not something WWE would want to associate with, it’s still an interesting prospect to consider.
Subject: Former UFC fighter training at the performance center 
