Floyd Mayweather Jr., the world-renowned pound-for-pound champion who knocked out his most recent opponent with two unexpected punches after being head-butted, has decided to pass on the opportunity to fight the other man many believe is the best pound-for-pound fighter, Manny Pacquiao.

I'm fighting Miguel Cotto on May 5 because Miss Pac Man is ducking me, said Mayweather on his official Facebook page.

Mayweather is required to report to jail in Clark County, Nev., by June 1 because of a plea deal in a domestic violence case.

The Nevada State Athletic Commission, the organization that grants boxers the right to fight at popular Las Vegas hotels, has granted Mayweather a one-fight, conditional license for May 5, so long as he complies with all of the judge's orders in his criminal case. Mayweather will be required to reapply for a license if he wants to fight again in 2012 after serving his 90-day jail sentence.

Cotto, who is promoted by the same company as Pacquiao, is coming of a TKO victory over longtime rival Antonio Margarito. Cotto currently holds the WBA super welterweight (154 lbs.) belt, which will be up for grabs when he and Mayweather meet on May 5.

Mayweather will move up to the super welterweight class in order to fight Cotto, something he hasn't done since his record-breaking pay-per-view fight against Oscar de la Hoya in May 2007.

It will be a challenge for me to compete with him at this weight, but this is the type of test I thrive on and gives me the motivation to train even harder. I have no doubt in my mind that my title belt collection will increase once again and Cotto's reign as champion will come to an end on May 5, Mayweather said in a USA Today interview.

HBO Sports president Ken Hershman told the AP that he thinks the mega-fight everyone is waiting for -- Pacquiao vs. Mayweather --has an expiration date of late 2012 or early 2014. After that, Hershman says it becomes less and less relevant.

Pacquiao has not made any announcements about who he'll fight next. He has yet to comment on Mayweather's decision to fight Cotto, either.

Pacquiao is coming off of a majority decision victory over his rival Juan Manuel Marquez. Though the men have fought three times, each contest has been close. The first of their battles was a draw, and Pacquiao walked away with victories by decision in both their second and third fight.

Pacquiao defeated Cotto in Nov. 2009 by TKO. In that fight, Pacquiao landed 336 of 780 punches (43 percent) compared to Cotto, who landed 172 out of 597 (29 percent). By the end of the fight, Cotto was forced to retreat with a battered face until the referee stopped the fight.