With Canelo Alvarez set to fight Liam Smith on September 17, one of the bits that has gotten out is that Golden Boy was interested in matching Alvarez with Manny Pacquiao, but that they had "heard" that Pacquiao had a deal in place to come back to boxing and fight Adrien Broner.
Lance Pugmire of the LA Times tweeted about that rumor today, quoting promoter Bob Arum:
This doesn't tell us anything definitive by any means, and Golden Boy saying they've "heard" that Pacquiao was going to fight Broner may simply be a way of trying to save face with a fight that is far less marketable -- "well we were told he's fighting Broner, so we can't make that fight, instead we have this" -- but there is something here, at any rate. And, shit, we spent weeks on end talking about the ridiculous fantasy of Floyd Mayweather vs Conor McGregor. At least this is two professionals from the same sport.
Pacquiao (58-6-2, 38 KO) is coming off of an April 9 win over Timothy Bradley Jr, which was supposedly Manny's retirement fight, but the fighter himself never really committed to that answer, saying he'd see how he felt. He's since been elected to a Senate seat in the Philippines, but even still, boxing is boxing, and fighters go back on "retirements" all the time.
Broner (32-2, 24 KO) last fought on April 1, struggling a bit in a win over Ashley Theophane. Broner lost his 140-pound belt on the scales the day before that fight, and a bout with Pacquiao would undoubtedly be at 147 pounds, where Broner controversially won a belt in 2013 by beating Paulie Malignaggi, before losing in his first defense against Marcos Maidana. In 2015, Broner lost another welterweight bout (well, a 144-pound catchweight) against Shawn Porter.
Following his win over Theophane, Broner called out his opponent's promoter, Floyd Mayweather, who is also supposedly retired. There was some belief that Mayweather would face Broner in the fall, but that hasn't picked up much steam since that week in early April. So now we have Broner possibly facing Pacquiao, maybe looking to do better than his former (?) "big brother" did with his 2015 win over Manny.
There's no timetable for this rumor right now, but one would expect it to happen in October or November, if it does happen in 2016.