LAS VEGAS >> Manny Pacquiao may meet an old foe in a new place in September.

Promoter Bob Arum says he is trying to put together a fifth fight between Pacquiao and Juan Manuel Marquez and shopping it to casinos in Macau and Singapore. He said Saturday night at the Brandon Rios-Mike Alvarado fight that the bout would likely be at one of the Venetian hotel-casinos in Macau or Singapore.

Marquez would be the most likely opponent for Pacquiao, though Arum indicated earlier that Timothy Bradley — who won a disputed decision over Pacquiao last year — is another possibility.

Marquez knocked Pacquiao out in the sixth round in December, flattening the Filipino fighter with a right hand that left him face down on the canvas for 2 minutes. It was the first win for Marquez in four fights between the two rivals.