Bayern Munich coach Louis van Gaal said Thursday that French playmaker Franck Ribery may not resume his national duty for another month with a niggling knee injury.

The 26-year-old midfielder has missed the Bundesliga club's 2-1defeat to Girondins Bordeaux on Wednesday and is quite doubtful for France's World Cup qualifiers against Ireland on Nov. 14 and 18.

He picked up the injury during pre-season training and has not fully recovered since.

"We have decided to allow the injury to heal," said Van Gaal after Wednesday's Champions League match at the French Ligue 1 club. "This could last up to a month."

France must get past Ireland to reach the 2010 World Cup finals in South Africa.