Promoter Bob Arum told The Times on Tuesday that Pacquiao's bout has been confirmed for April 9 at MGM Grand in Las Vegas.
The announcement will be made from Puerto Rico on a truTV broadcast of a card featuring the country's gifted fighter, Felix Verdejo.
World Boxing Organization welterweight champion Bradley (33-1-1, 13 knockouts) is coming off an impressive ninth-round stoppage of Brandon Rios on Nov. 7 in Las Vegas, his first bout with new trainer Teddy Atlas.
Bradley's manager, his wife, Monica Bradley, said nothing's final, but she's been in talks with Top Rank President Todd duBoef.
"A lot can change in the next three days, but Todd and I have developed a good relationship. I like the way we do business," Monica Bradley said.
An official close to Arum's promotional company, Top Rank Inc., said those conversations have been about finalizing purse money, while such talks have not taken place with Pacquiao's other possible choice, unbeaten junior-welterweight champion Terence Crawford.
Bradley won a highly disputed 2012 split decision over Pacquiao, then was beaten by unanimous decision in their April 2014 rematch.
"Tim's very excited – more about this one than either of the others before," Monica Bradley said. "With a new trainer, it'll be a whole different Tim Bradley. Teddy has done so much for Tim … people might think they've seen the best Tim Bradley. They haven't yet."
Pacquiao (57-6-2), who'll turn 37 on Dec. 17, hasn't fought since reaggravating a shoulder injury in his May 2 unanimous-decision loss to Floyd Mayweather Jr. – the richest fight in history.
Arum has said the April 9 bout will be Pacquiao's final fight as he seeks a seat in the Senate in the Philippines, but Pacquiao has been quoted in his home country as saying he'd like another crack at Mayweather, who announced his retirement following a September victory.
Bradley will be in Puerto Rico as an analyst on the fight broadcast and Crawford has been invited to the island for the announcement, his manager Cameron Dunkin said.
Dunkin said Crawford is scheduled to fight on two HBO cards and a pay-per-view bout in 2016, with opponents including Lucas Matthysse, Ruslan Provodnikov and fellow 140-pound champion Viktor Postol in play.