UFC 137 Fight Card: What a Loss Would Mean for BJ Penn

Throughout his storied career, BJ Penn has faced the best competition the UFC has had to offer. That trend will continue when he pairs up with Nick Diaz to headline UFC 137. 

Penn's mentality heading into his bouts has always been a potential weakness of his, but leading up to his bout with Diaz, he has appeared much calmer and less intense than before. While that doesn't imply that he isn't focused, it is certainly not something most fans are accustomed to seeing out of the Hawaiian prior to a fight.

Both Penn and Diaz are heading into the main event with pressure riding on them, partially to help save one of the most anticipated cards of the year. Penn's situation is entirely different from Diaz's, however. 

For as much success he has captured at lightweight, his transition to 170 pounds hasn't fared so well. His dominant win over Matt Hughes at UFC 123 was an indication of what Penn is capable of, but an uninspiring performance against Jon Fitch erased Penn's chances at earning another title shot. 

He gets his second chance to prove that he is still a worthy contender against Diaz. 

Although, should he come up short against the Strikeforce welterweight champion, talks of retirement will begin to resurface and Penn's future in the sport will be also be questioned. Certainly, a competitor of Penn's caliber has all the potential to be successful at both weight classes, but it has been struggle for him to do it. 

He will face a aggressive, durable scrapper in Diaz—one who could potentially cause problems for Penn. 

While he is regarded as the greatest lightweight of all-time, Penn's missed opportunities at capturing the welterweight title have always hindered him from exceeding expectations and reaching his full potential as a mixed martial artist. 

Should he fail to get past Diaz, we might never know of Penn's ability to compete at 170 pounds.