MUNICH: Three of Bayern Munich's key players will be missing in the next few matches because of injuries, coach Pep Guardiola said on Friday.

Speaking ahead of the Bundesliga match at Borussia Moenchengladbach on Saturday, Guardiola said winger Douglas Costa has a thigh strain, and winger Arjen Robben a calf injury. Midfielder David Alaba's left ankle injury is proving more serious than originally believed, and he is not expected to play again before the Christmas break.

"I hope he'll be able to train with us at the start of the new year," Guardiola said.

Bayern has 13 wins and one draw in its first 14 Bundesliga matches, and will be seeking to end Moenchengladbach's nine-match unbeaten run under new coach Andre Schubert.

Costa has proved to be a more than adequate replacement for Franck Ribery, who has not played since March because of an ankle injury, but returned to training this week.

Guardiola said it was "possible" Costa could be fit in time for the last match of the year at Hannover, but added that he would be taking no risks.

"What matters is that they're all 100 percent fit after the winter break," Guardiola said.

He gave no date for the return of Robben.

"He's told us he is not fit," the coach said.

Guardiola praised Ribery's effort in training: "He will come back this year. For sure."

Juan Bernat, Thiago Alcantara, and Mario Goetze are also on the long-term injury list, with the first two possibly returning to training next week.

Next week, Bayern plays Dinamo Zagreb in the Champions League having already qualified for the knockout stage.

It also plays Darmstadt in the German Cup, and has remaining matches against Ingolstadt and Hannover in the Bundesliga.