Manny Pacquiao has said he plans to retire after his fight against Timothy Bradley on April 9, but not everyone believes that the boxer will call it quits. Top Rank CEO Bob Arum said he wouldn’t be surprised to see his client back in the ring after his next fight.

"Once that bell rings for that final round, Manny Pacquiao's going to rethink it and who knows if he decides to return?" he told AFP in Hong Kong.

"I've been in this boxing business for 50 years and I know that fighters retire and other than, say, Rocky Marciano, they come back," said the 84-year-old Arum.

"Will it be Manny's last fight? I'm not ready to guarantee that."

Pacquiao is 37 years old and has stated he plans to concentrate on his political career after facing Bradley. But it could be difficult for him to walk away from a major payday. Reports surfaced in 2014 over tax evasion issues, and he hasn’t fought in nearly a year because of shoulder surgery. 

A big-time fight might draw Pacquiao back into the ring, though that bout might not currently exist. He’s facing Bradley for a third time, having run out of top names to fight.

The one bout that could potentially end Pacquiao’s retirement might be a rematch with Floyd Mayweather. Pacquiao lost a unanimous decision to Mayweather in May, but he earned more than $100 million for one night’s work.

Mayweather announced his retirement after beating Andre Berto in September, but Arum won’t rule out another fight between the two boxers.

"I'd love to see a Mayweather-Pacquiao second fight, of course I would," said Arum. "The first fight was by far the most lucrative in the history of boxing.

"But Mayweather has to un-retire, Manny has to decide whether or not he's elected to the senate and he'll do the rematch, so we'll have to see.”

Mayweather has taken a break from boxing before, only to return after taking a 19-month sabbatical between Dec. 2007 and Dec. 2009.  But the 38-year-old amassed a large fortune after making his professional debut in 1996 and even publicly rescinded a possible rematch with Pacquiao not long after their fight. Ending his career at 49-0 and proving that he is the best fighter of his generation, not Pacquiao, Mayweather may choose to remain retired rather than risk a loss. 

However, Mayweather made well over $200 million for the May fight, and it might be difficult to rule out a comeback with another huge offer on the table. Meanwhile, Pacquiao would likely prefer one last shot at Mayweather, believing he was robbed of a victory, and having fought with an injured shoulder.

Pacquiao hasn’t won a fight since Nov. 2014 when he defeated Chris Algieri, and has lost three of his last six bouts.