UFC 137 Results: 5 Reasons B.J. Penn Should Return to Lightweight, Not Retire

After Nick Diaz worked him over for three rounds at UFC 137, B.J. Penn casually dropped a little bomb on the MMA world when he announced his retirement from the Octagon.

Though, at this point, there appears to be no reason not to believe Penn, he has tossed around the R- word before, including after his fight with Jon Fitch last year. And it would seem that such sweeping decisions aren't always best made five minutes after getting punched in the face for 15 minutes in front of millions of people. Perhaps in a week or two, cooler (and less bloody) heads may reach a different decision.

And from a selfish perspective, here's hoping they do. Penn had a bad night against Diaz, but he could very well have plenty more fight left in him. Personally, I think he could get the most our of his remaining years if we were to return to—and stay in—the lightweight division. Here are five reasons why.

5. Better Cardio

It was clear Penn grew exhausted against Diaz. He wasn't the first and won't be the last to suffer that fate against Diaz, who has some of the best cardio in the business.

But there's no question Penn is simply in better shape when he's fighting as a lightweight. It's not like he's adding 15 pounds of lean muscle every time he moves up. 

4. Better Fights to Be Made

Yes, I'm aware that Penn has lost twice to current lightweight champ Frankie Edgar. The flip side, of course, is that he has also lost twice to current welterweight champ Georges St-Pierre.

Penn may no longer be championship-caliber material at any weight class. That's just the reality of an athlete's career arc. But it doesn't mean he can't still fight at a very high level. At lightweight, he could be something of a gatekeeper emeritus.

There are many more interesting matchups for Penn at 155. How about Clay Guida? Donald Cerrone? Ben Henderson? There are good matchups at welterweight, too, but none that would seem truly compelling beyond a novelty standpoint. If you really want to watch Penn slog through a rematch with Jon Fitch or get thrown to Carlos Condit or Jake Ellenberger.

3. He's Won More Fights at Lightweight

When your back's against the wall, you gotta dance with the horse that brought you. Or something like that.

For Penn, that's clearly the lightweight division, where he has a career record of 11-3-1, compared to 3-3-1 at welterweight. He also has a two-year title reign there.

2. It's His Natural Weight Class

B.J. Penn is not a big welterweight. He's not a hulking lightweight, but at a stage when his pure athletic brilliance may be eroding, it's probably best to maximize the gifts you do have.

1. Change Is Good, Particularly for B.J. Penn

Anyone who has followed Penn's career can attest to its inherent restlessness. Not only has he shuttled back and forth between lightweight and welterweight, he's also tried his hand as a K-1 kick boxer, as an MMA middleweight and even an open weight bout with natural light heavyweight Lyoto Machida.

So for a guy for whom change appears to be the only constant, maybe a change of scenery—and not a full-scale retirement—would satisfy Penn's need to take action.