Joe Calzaghe's promoter Frank Warren is set to offer middleweight king Jermain Taylor £3m for a super-fight in July to probably take place in Britain.
Calzaghe made the 20th defence of his WBO belt with a third-round win over Peter Manfredo in Cardiff on Saturday.
Warren said Denmark's WBC and WBA super middleweight champion Mikkel Kessler had rejected a summer unification bout.
"Joe's got no problems fighting those guys. Maybe Kessler will rethink or maybe Taylor will take it," he said.
"I spoke to Kessler's promoter Morgen Palle last week, sent him an offer and he sent me a fax back yesterday saying that Kessler won't be ready in July.
"Why, I do not know, because he was calling Joe out after his last fight. But you can't force him to fight. I'd love it to be him because his style really suits Joe.
"How can you not be ready in four months' time? It's crazy. He also said he'd want half the purse.
"But how a guy who's had a few defences of his title has parity with a guy who's had 20, I don't know.
"In the meantime, we're offering Jermain Taylor £3m to fight Joe in July, and American television network HBO have talked about fighting Bernard Hopkins in January, so we'll see what happens."
Warren also scoffed at the idea that Calzaghe needs to go to America to prove himself as a great fighter.
"Guys want to get paid big money, so you go where you can generate the money," said Warren.
"Would Joe get a bigger crowd in the States than if he fought Taylor here? I don't think so. And anyway, this fight was shown live on TV in the States.
"I don't get this idea of 'if you don't go to the States, you haven't made it'. Tonight, 35,000 people got to see their champion, and that's what's important."
Meanwhile, Calzaghe insisted he had hurt Manfredo, despite admitting that the fight could have been stopped prematurely.
606: DEBATE
Referee Terry O'Connor called a halt after a barrage of blows from Calzaghe went unanswered by Manfredo, although few of them seemed to have landed.
"He was fighting for the title and wanted to go down fighting. I sympathise, he trained hard for this fight," said Calzaghe, 35.
"I'm not the referee. It could have been slightly premature, but I'm just in there throwing punches. He was slightly hurt, the body shots stunned him a little bit."
Manfredo, on the other hand, was adamant that the fight had been called off too soon.
"I'd rather get killed than be stopped. The referee had no right to stop the fight like that."
"Of course it was premature - did you see my legs buckle? The referee didn't even say 'throw some punches back or I'll stop it', there was no warning," said Manfredo.
"It was a 10 second attack by him, he got a couple of shots in but most of them were around the gloves if that.
"I'm not here to cry about it, but I trained hard for 12 weeks to come here and win and I'm in shock that he stopped it that quick.
"I'd rather get killed than be stopped. He had no right to stop the fight like that. This ain't the amateurs, this is professional boxing for the world championship.
"The referee should be fined and they can give me the money. He gave Jeff Lacy a beating for 12 rounds, hit him with a million shots and they never even warned him."