Carlos Tevez was last night facing the prospect of the heaviest fine in British football history, though his legal battle may drag on for weeks as he fights a Manchester City inquiry which suspects he may have committed multiple breaches of his contract.

Tevez may receive a fine of six weeks' wages – £1.5m – and/or a six-week ban, after the club's two-week investigation into manager Roberto Mancini's allegation that he refused to enter the field of play when the club were 2-0 down at Bayern Munich last month found that "there is a case for Carlos Tevez to answer, of alleged breaches of contract."

Tevez demanded that Mancini retract his allegation when he met with his employers in central London, hours after arriving back in Britain yesterday, but despite his own claim that 15 statements support his version of events in Munich, it is understood that City's internal inquiry has turned up no evidence from City staff present at the Allianz Arena that contradicts Mancini's case.

Tevez claims that he refused to warm up, rather than to play, and is ready to appeal any sanction the club imposes on him through the club's main board and through the Premier League, if necessary. City are understood to believe that the mere failure to warm up itself constitutes a serious breach of his £250,000-a-week contract, though a television interview – mistranslated according to his advisers – forms part of the evidence that he also refused to play.

City's determination to follow the disciplinary procedures to the letter mean that Tevez has been asked to present himself at training at Carrington today, where Mancini will tell him he is working with the reserves. The City board will support whatever course of work Mancini outlines for the player pending the completion of the disciplinary procedure. He will travel to the training ground willingly, considering himself still to be a first-team player at the club.

Sacking Tevez is not an option but the lesser sanction of a fine or extended ban still threatens to drag the club through the legal battle which Mancini is so desperate to avoid, for fear of the focus of City's season being lost. The dispute may drag on into December. Tevez will appear on Monday or Tuesday of next week at a disciplinary hearing chaired by a senior member of City's executive leadership team – either football operations officer Brian Marwood or acting chief executive John MacBeath. If that hearing supports the internal inquiry's findings, he may then appeal to the main board and then make the fairly unusual move of appealing to a Premier League arbitration panel. The 27-year-old believes this could take him up to Christmas, though City are desperate to have the issue resolved far sooner. The last player to seek recourse through the Premier League was Charlie Adam, who won a disputed £25,000 bonus from Blackpool last season.

Another dramatic day in the life of Tevez began when he landed at Heathrow at 6.40am yesterday. He attended a central London meeting with two members of City's staff – believed to be members of the HR and legal departments – and it was at that meeting that he demanded the Mancini retraction, as a way of resolving the dispute. But for City, the meeting was an opportunity to allow Tevez the chance to offer final evidence to an inquiry which had already found against him and it was last night that he received notification that he would be facing full disciplinary procedures.

City's confidence is based on the fact that the Professional Footballers' Association are understood to agree with their assertion that the club are right to fine or suspend Tevez for more than the usual two-week maximum. A six-week fine will take him way beyond the £150,000 and five-game ban handed to Manchester United's Roy Keane for bringing the game into disrepute over the account of his challenge on City's Alfie Haaland in his autobiography in 2002 . The club had to make the PFA aware of their findings, under the terms of an agreement reached with the players' union 10 years ago when the minimum two-week penalty was extended to six.

The real challenge for City is now to get Tevez off their books. Juventus general director Giuseppe Marotta yesterday denied reports that his club have started negotiations. If a sale cannot be concluded, then City have a problem. Under employment law governing football, a player cannot be repeatedly denied the chance of first-team football if he is capable of it and may effectively sue a club for constructive dismissal.