Guardiola, speaking in Rotterdam ahead of tonight’s Champions League opener, simply said a “sporting decision” had been made to omit the veteran midfielder from his squad.

The City boss added that the full reason would be kept between himself and the player.

The matter raises fresh questions over the 34-year-old’s future at the Etihad Stadium.

Guardiola said: “I spoke with him and he knows the reason why, but its between him and me. It’s a ‘sportive’ decision.”

Toure was an unused substitute for City’s first three games of the season before being left out of the matchday squad for Saturday’s Premier League defeat of Liverpool. It is now clear Toure was not injured.

Toure was left out by Guardiola at the start of last season, a decision which sparked a row with his outspoken agent Dimitri Seluk. That, in turn, led to a longer period of isolation from the side for the Ivorian. That issue was eventually resolved and Toure went on to regain a place and play an influential role in the second half of the season.

Guardiola said: “Yaya was so important last season. Six players finished contracts last season and the only one who stayed was Yaya, because he is a special player.

“But the decision was he didn’t play the last game and today he was not in the squad. He knows the reason why. Hopefully he’ll play soon, but it depends on him.”

Guardiola is yet to make a decision on the fitness of goalkeeper Ederson. The Brazilian has been training wearing protective headgear after suffering facial injuries which required eight stitches in a nasty clash with Liverpool’s Sadio Mane at the weekend.

Vincent Kompany is out, troubled by a calf injury. City are hoping to make a stronger showing in the Champions League this season after falling below expectations last term and exiting at the last-16 stage.

Guardiola, a two-time winner as a coach with Barcelona, made clear there is no room for complacency in a Group F campaign that begins with the Dutch champions and also features Napoli and Shakhtar Donetsk.

He said: “We play our first game in the group stage. It is a dream to be here again for a club like Manchester City. We fought a lot to be here because the gap was so close.

“We start our road. I know how complicated it is. Last year we were not able to win one game away.”

Feyenoord boss Giovanni van Bronckhorst believes City are good enough to win the competition.

Former Arsenal man Van Bronckhorst said: “They have had a good start to the season, they are a big club with a good coach and great players.

“I have seen a couple of matches and they are one of the best teams in Europe. It is a big task for us but a big opportunity for us to get a result.

“If you have a squad like Man City have, players with a lot of qualities and experience - for me it is one of the teams that can win the Champions League. It is a big task but we are a good team, a good collective, especially at home.”