By Rick Reeno

Thomas & Mack Center, Las Vegas - Top Rank's CEO Bob Arum, who promotes WBO welterweight champion Manny Pacquiao (59-6-2, 38KOs), has no shortage of options for the fighting senator.

An important figure was sitting at ringside and taking in the action - Floyd Mayweather Jr. (49-0, 26KOs).  Last May, Mayweather won a twelve round decision over Pacquiao. The Filipino star, and his trainer Freddie Roach, have been hunting for a rematch ever since. 

But Arum is not even thinking about Mayweather, who retired from the sport last September. Retired or not, a Mayweather vs. Pacquiao rematch - for better or for worse - is the most lucrative fight in boxing.

"As far as we're concerned Mayweather is retired," Arum said. "[Why did Mayweather show up?] - that's a question that you should ask Mayweather, not me."

Outside of a Mayweather rematch, Arum has several potential options in mind - including WBC/WBO junior welterweight champion Terence Crawford, WBO super featherweight champion Vasyl Lomachenko, WBA welterweight champion Keith Thurman and WBC welterweight champion Danny Garcia.

Crawford is back on December 10th, when he defends his titles against John Molina in Omaha. Lomachenko is set to defend his title against Nicholas Walters on November 26th in Las Vegas. Arum would like to make Pacquiao-Lomachenko at a catch-weight of 135 or 140. Garcia and Thurman are penciled in to unify their titles on March 4th.

"Off the cuff, without really exploring all options - I would say Terence Crawford, who has a tough fight coming up on December 10th on HBO.... Vasyl Lomachenko, who has a tough fight coming up right here at the Cosmo on November 26th - which will also be televised on HBO. And maybe depending on the timing, Danny Garcia or Thurman could be possibilities. All of those guys would be in the mix," Arum said.