Ultimate Fighting Championship welterweight titleholder Georges St. Pierre and UFC lightweight champion B.J. Penn will rematch on Jan. 31 for the 170-pound belt. If Penn wins, he's expected to defend both titles. If St. Pierre emerges victorious, it could lead to a mega-fight with middleweight titleholder Anderson Silva to make a strong case for who is the pound-for-pound best fighter in the world.

"If Georges wins, obviously there's another super-fight lined up for him that he could possibly take," said UFC President Dana White, alluding to a bout with Anderson Silva.

"Hypothetically speaking, if he (St. Pierre) beat B.J. Penn that night, it would be up in the air who is pound-for-pound the best in the world," added White. "Who knows what we'd do, but it's obviously a very interesting fight. If he beats B.J."

While a win will likely garner St. Pierre a shot at Silva, if Penn wins on Jan. 31, he isn't apt to get the opportunity to move up and challenge the 185-pound titleholder, a fight that Penn has already voiced interest in.

"B.J. doesn't have the frame to carry that kind of weight," stated White. "Is he tough enough to do it? Absolutely. Is he talented enough to go up there and do it? Absolutely. Does that mean he should do it? Absolutely not. He doesn't have the frame to carry that kind of weight. And it just makes no sense, no sense at all."

Penn has a 2-0 record as a middleweight with wins over Rodrigo and Renzo Gracie and has competed as high as heavyweight, losing a decision to the undefeated Lyoto Machida.

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