Ballack is understood to want to leave Bayern after one final season in the Bundesliga and The Guardian reports that the preliminary details of a free transfer have been provisionally agreed for him to sign a pre-contract agreement at Old Trafford next January.

But the player's agent, Michael Becker, said no deal had been struck.

"There's no pre-contract, no gentleman's agreement," he said.

"The only people we're talking to at the moment are Bayern."

United were understood to believe they have a gentleman's agreement in place with Ballack who has 57 international caps plus 61 goals in 206 Bundesliga matches.

His arrival would signal the end of Roy Keane's career at Old Trafrord.

But Bayern insisted Tuesday they had already offered Ballack a much-improved new contract.

"Everything's in Ballack's hands. I'd advise him to seize the opportunity," said Bayern president Franz Beckenbauer.

But Bayern coach Felix Magath admitted there was a danger they could lose the play-maker, who will be 29 in September,

"Of course we want him to stay, but it's in his hands," he said.

Ballack turned down Real Madrid to join Bayern from Bayer Leverkusen in 2002.