Berlin - Bayern Munich winger Franck Ribery is increasingly frustrated by his troublesome left knee injury, which will keep the Frenchman out indefinitely.
The former Marseille striker, missed Bayern's narrow 1-0 victory over Manchester City in their Champions League group phase opener on Wednesday, and has only played 23 minutes of the new season.
"It's really annoying," the 31-year-old told Kicker magazine on Thursday.
When asked about a possible return to action, Ribery, who recently announced his international retirement from the French team, replied; "I don't know".
He scored in Saturday's 2-0 Bundesliga victory over Stuttgart, his first appearance of the season, but felt pain in his knee tendons during training on Monday and coach Pep Guardiola is equally concerned about one of his prize assets.
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"I think he won't be playing in the upcoming days," said the former Barcelona coach.
Bayern chairman Karl-Heinze Rummenigge added he is more optimistic about Ribery's return to action rather than injured midfielder and World Cup winner Bastian Schweinsteiger, who has yet to play this season.
"For Ribery, it will be quicker than Bastian. In his case (Ribery), the medical staff are expecting a short term injury and not a long one," said Rummenigge.
Schweinsteiger is also suffering from a knee problem and hasn't played since Germany won their fourth World Cup in Brazil last July.
Bayern are joint top of the table, alongside Bayer Leverkusen and Hanover, on seven points from three outings, as they get set to travel to Hamburg on Saturday before a home fixture against Paderborn, three days later.