UFC 137 Results: B.J. Penn Unexpectedly Retires After Loss To Nick Diaz

Mirko "Cro Cop" may not have been the only legend to make his final appearance Saturday night at UFC 137. Following a brutal decision loss to Nick Diaz, welterweight headliner B.J. Penn unexpectedly called it a career.

"This is probably the last time you'll ever see me here," an emotional Penn said to Joe Rogan after the loss. "I've got a daughter, another daughter on the way. I don't want to go home looking like this. I'm done."

If Penn's surprising revelation proves to be true, it would be a unfortunate ending for one of the most legendary fighters in UFC history. In ten years and 21 fights with the promotion, "The Prodigy" has amassed a 16-8-2 record en route to becoming the second fighter in UFC history to win titles in two different weight classes, earning wins over Matt Hughes (x2), Diego Sanchez, Jens Pulver, Kenny Florian, Takanori Gomi, Renzo Gracie, and Sean Sherk in the process.

"B.J's the man," Diaz declared. "I always love watching him fight."