Manchester - Manchester City manager Pep Guardiola admits he does not know when injury-plagued French international full-back Benjamin Mendy will be back in action after he suffered a metatarsal injury.

Mendy, who missed nine months last season after requiring surgery on a knee ligament injury, is believed to have suffered the injury in training after returning from international duty with France at the start of the month.

He has missed City's last two games, the win over Fulham and a disappointing Champions League group-stage defeat at home by French outfit Lyon in which Fabian Delph played poorly in his left-back position.

Guardiola refused to expand upon the exact nature of Mendy's injury although City later described it as a "bruised" metatarsal.

Guardiola, however, hardly cleared up the uncertainty and claimed not to know how long he will be without the 24-year-old defender for.

"He has a problem in the bone of his feet, I don't know (when he will be back)," said Guardiola.

Better news for City fans is that Belgian star Kevin De Bruyne appears to be making a good recovery from his knee ligament injury which has prevented him playing since August.

The 27-year-old - who had a fine World Cup as Belgium lost to eventual champions France in the semi-finals - himself predicts he will be fit to return for the first Manchester derby of the season on November 11, although Guardiola refused to confirm that.

"I don't know," said Guardiola at his press conference on the eve of their away trip to Premier League strugglers Cardiff.

"I speak with the doctor sometimes and he's telling me he's going so well.

"But I don't know. He has to come back. The important thing is when he comes back, he is completely fit and finishes the rest of the season."