Bayern Munich winger Arjen Robben will be out for an undetermined period of time to allow treatment on his groin problem.

Team doctor Hans-Wilhelm Mueller-Wohlfahrt told the club's website Wednesday that Robben needs ''intensive treatment'' on the bone inflammation which kept the Dutch winger out of Bayern's Champions League second leg playoff in Zurich on Tuesday.

Dr. Mueller-Wohlfahrt said ''the period of his recovery cannot be set at this time.'' The 27-year-old Robben will be evaluated on a daily basis to see how he progresses.

Robben has been beset by back and groin problems since Bayern's season begun.

Robben had been due to play in the Netherlands' 2012 European Championship qualifier against San Marino on Sept. 2.

''We have to clear that up with the Dutch federation,'' Bayern coach Jupp Heynckes said.