"I think I should stay retired," he said. "One thing I know is that I put a lot of effort, a lot of energy into this camp. I trained for the last year to do this camp, to do this fight. After the last few fights, I'm kind of getting tired (of training)."
Penn returned earlier this year, moving down to featherweight for the first time in his career. He suffered a third loss to Frankie Edgar, the same fighter who took the lightweight title from him in 2010. The Hawaiian will turn 36 in December.
- UFC female bantamweight champion Ronda Rousey isn't just blowing smoke when she says Gina Carano would be her biggest challenge. Despite not fighting for several years, Rousey feels Carano can step in and give her a run for her money.
"I really do believe that she's the hardest competitor I could ever find to fight," said Rousey, during a recent interview with ESPN. "Even if you don't believe that, even if you think she took too much time off and it'd be a quick fight, to be honest, that fight would be too hot not to watch. It doesn't really matter if it'll be competitive or not. And if you do what it, you're going to be surprised: It'll be one of the greatest fights to ever happen in the history of women's MMA."
Rousey (10-0) has stated a desire to fight on the year-end card, as she did last year. Carano (7-1) remains unsigned, but UFC president Dana White has reached out numerous times to her representatives.
- Despite possibly facing a lengthy suspension for his decision to not take a drug test earlier this year, Wanderlei Silva remains hopeful for a fight to be made. And he has his sights set on Dan Henderson.
Henderson, looking to get back in the Octagon later this year, responded via Twitter to the fight proposal by "The Axe Murderer." Henderson and Silva have squared off twice, with the Brazilian winning the first via decision in 2000 and the American avenging the loss in 2007 via third round knockout.
Got a news tip or correction? Send it to us by clicking here.
UFC Fight Night 79 Results: Former Champion Leaving UFC, Ben Henderson In Big Fight, Bonuses, More
Photos: Matt Hardy Bleeds, Who Won The First-Ever Hardy Vs. Jeff Jarrett Match?
Jim Ross Blogs About Stars WWE Can Bring In For WrestleMania 32, Daniel Bryan Not Getting Cleared
Daniel Bryan's Trainer Talks About Working With Shawn Michaels, His Attitude, Training Bryan, More
Most Personal WWE Grudges Of All-Time, Xavier Woods And JoJo Play Power Rangers, More
Sound Off: What Will Be The WWE Championship Match At WrestleMania 32?
William Regal Reveals His Favorite Wrestling Moment; Talks Dressing In Drag On RAW, More
Raven On Why He Recently Sued WWE, Drinking With Shane McMahon, Impressing Vince McMahon, More
WWE Legend Pulled Due To Health, The Wyatts Vs. The Dudleyz, The Undertaker Gets WWE DVD Cover
Kurt Angle Talks About His Best Friends In WWE, Brock Lesnar Demanding To Lose To Him, Best Workers
NJPW Owner Says New WWE Signing Is A "Massive Shame", New WWE Coach Helping To Teach English?
Solomon Crowe's First Tweet Since Release, ECW Original Injured In Car Accident, WWE NXT DVD Note