Roberto Mancini's uneasy relationship with Carlos Tevez is threatening the player's future at Manchester City after the manager confirmed they had clashed behind the scenes. The Italian said the forward should leave the club if he is unhappy with his coaching methods.

Mancini confirmed he had summoned Tevez to his office to ask for an explanation about the player's recent criticisms of his training regime. The Italian told his leading scorer he would not tolerate any more of this, regardless of the fact that Tevez has scored 28 goals this season and is the overwhelming choice to be named City's player of the year. The two men shook hands at the end of a largely one-sided conversation and agreed to focus on City's remaining three games of the season but stories have emerged this week of the Argentinian considering his future.

Asked if he thought Tevez might be unhappy, Mancini replied: "I don't know. Tevez has four years left on his contract. But I don't know. If he's not happy, it would be better [for him] to change squads. If a top player is not happy to stay here, then it's better for him to go to another team."

Tevez upset Mancini by complaining about the manager's habit of arranging double training sessions. Mancini does this every Tuesday if there is no midweek game and Tevez said: "The players are not happy with this. We are at the end of a long season, we have big matches, we are tired, but there are still double training sessions, morning and afternoon. "

This was in an interview in the Daily Mail in the week preceding the Manchester derby, when Tevez had been specifically asked not to speak to the media. He went on to say he was "OK" with Mancini but the former Internazionale coach felt his authority had been undermined by a player he has repeatedly talked up as being one of the best in the world.

At the time Mancini said he did not want to take issue with the former United striker before such an important game. The timing is still bad from a City perspective, with important games coming up against Aston Villa and Tottenham Hotspur in the next few days, but Mancini was willing to explain his irritation as he shaped up for the most critical phase of City's season.

Mancini said today: "I've spoken to Tevez. What we said was private but I did remind him that there had been only one time when he had to train twice in a day.We have trained twice four times in the five months I have been here. On two of those times Carlos was in Argentina and one time he was here but didn't train. So I don't know why [he's unhappy]. When we don't have a midweek game I always train two times on Tuesday because it's the only way I know."

Mancini added: "It's important that when a manager or player works in a team, he must be happy. If he's not, it's not good for the club, for the squad, or for the player. This is not just for Tevez but for all the players; for Tevez, for Manu [Emmanuel Adebayor], for me, for everyone.

"I don't know if Carlos Tevez is unhappy. He must be content, though, because we have to play three important games. For the players it is a crucial moment. They must put everything they have on the pitch."

Tevez, whose English is still limited, did not offer an apology. "When I speak to a player, I don't need an apology," Mancini said. "I've played football, I know players very well and I know these situations. I think he's happy because he's worked very well the last two weeks. I hope Carlos can score three or four goals in the next three games and afterwards we can decide if he has a problem."