The French winger has been suffering from a number of minor injuries since he returned to the Bayern trainings in early July, including blistered feet and knee problems.

"Franck has a lot of catching-up to do. He trained hard and went further than last week but it has been limited nevertheless," Van Gaal told Bayern's official website.

Van Gaal added that if Ribery regains full fitness ahead of the game, he will not play for more than 20 minutes.

In addition to Ribery, the Bavarians will have to do good without Croatian forward Ivica Olic and Italy striker Luca Toni, who are both out with injuries.

Ribery has been the subject of transfer speculation this summer, as Bayern has so far been successful in keeping him out of Real Madrid's reach.

The Spanish giants, who were keen on landing the 26-year-old, were put off by Bayern's asking price of 80 million Euros.