Unbeaten US star Mayweather and Pacquiao, regarded as the world's top pound-for-pound fighters, nearly made a deal for a fight once before but the American's insistence on unique anti-doping blood tests helped kill the talks.
Ellerbe told ESPN that Mayweather called from Las Vegas to the Philippines after earlier this month calling out southpaw Pacquiao on Twitter, taunting "Step Up, Punk" to the world welterweight champion.
Mayweather has spoken with Pacquiao adviser Michael Koncz several times in recent weeks, according to all reports.
Pacquiao, 54-3 with two drawn and 32 knockouts, has won his past 15 fights over a span of nearly seven years while Mayweather, 42-0 with 26 knockouts, must serve a 90-day jail sentence starting June 1 after a domestic violence conviction.
Arum said that the issue of who Pacquiao would next fight would be resolved this coming week. Arum presented four other possible foes.