Joe Calzaghe's proposed unification bout with Mikkel Kessler could be held at Cardiff's Millennium Stadium.
Calzaghe attracted a record crowd in Wales for the Manfredo fight
Copenhagen's 40,000 capacity Parken Stadium was considered the most likely venue, but more fans would be expected at the 74,500-seat Cardiff arena.
Calzaghe's promoter Frank Warren says that plans for the fight are at a "very, very advanced stage."
Warren had wanted a September date, but Kessler's promoter Mogens Palle insists that he expects the fight in November.
Calzaghe, 35, attracted a European indoor record crowd of 35,000 for his 20th defence of the WBO super middleweight title againsty Peter Manfredo Jr at the Millennium Stadium in April.
Palle, who promotes 28-year-old undefeated WBA and WBC super middleweight champion Kessler, said on Wednesday that he had renewed an offer of £2.75m for Calzaghe to fight in Denmark in November.
"I never said September, it was always November," Palle told BBC Sport Wales.
"I sent the offer to Frank Warren on Tuesday, for Kessler to fight Calzaghe in Denmark in November with Calzaghe to receive $5.5m.
"He has said many times that he will come over here and destroy Kessler, I hope he will now accept this challenge and we will see how good Calzaghe really is."
Kessler holds both the WBA and WBC belts at super middleweight
Warren appeared to contradict Palle's version of events in an interview with BBC Radio Five Live earlier this month.
"Palle made an offer for Joe to fight Kessler in Denmark in September. We've accepted and are awaiting a contract," he said.
"It's not a done deal until it's signed but we've accepted. It's now up to Palle to send a contract.
"Joe doesn't mind fighting in Denmark. He feels he will beat Kessler anywhere and I believe that's the case as well.
It will be Joe's biggest payday but then he should be getting his biggest payday - Joe is box office
"It's a great fight. It's the two best super middleweights in the world. It's probably one of the most competitive fights at the moment in boxing.
"I'm hoping it's not all nonsense. He's been talking a lot about fighting Joe with Kessler and we've called his bluff. I don't believe he ever thought that Joe would go to Denmark.
"It will be Joe's biggest payday but then he should be getting his biggest payday. He's into his 21st defence. He's been champion for 10 years. Joe is box office."
Kessler's camp had previously accused Warren of shielding Calzaghe from a bout with the Dane, but Warren insists his boxer is ready to fight.