Things could get very interesting in the coming months, according to promoter Eddie Hearn of Matchroom Sport.
Last month, Hearn held a meeting with members of Manny Pacquiao's team to discuss the possibility of facing Amir Khan at the end of the year.
Khan is back in action on Saturday night in Birmingham, and he must walk away with a victory when he faces Samuel Vargas.
Should Khan win, he is very interested in facing Pacquiao for the WBA "regular" welterweight title.
But Hearn is still extremely eager to match Khan against fellow former champion Kell Brook.
A third option, could see Brook step in and fight Pacquiao - back at the welterweight limit.
Brook recently moved up to junior middleweight, and drilled Sergey Rabchenko in two rounds in March.
If Khan demands too much money for Pacquiao, then Hearn is going to offer up Brook to the Filipino superstar.
"Khan has a decision to make, if he beats Vargas, probably within two weeks, do you want Brook?," Hearn told Sky Sports.
"Brook has said to me, 'I want a big fight'. He was going to have a run-out at Wembley [on the Anthony Joshua-Alexander Povetkin bill], but he was just 'I want the big one'.
"I met with Pacquiao's people last week as well, and if Khan is too expensive for Pacquiao, because Pacquiao is very expensive, Pacquiao could fight Brook. But Brook is going to have to be at 147[lbs] to fight either of those two. He has to start now."
And Hearn reveals that Brook will have no issues with making the welterweight limit - if he starts training right now to properly make the weight without draining himself.
"He will make 147," said Hearn. "I still think he's better at 154, but if he's got 16 weeks to do it, he'll be okay. He said 'who am I fighting?' I said 'it doesn't matter, you may fight either of those guys, but you need to get into the gym now'.
"Could Brook steal the Pacquiao fight, and Amir is left with nothing? Is Brook about to gate crash the Pacquiao-Khan fight? It's wide open for anybody to fight anybody."
