Frau, who celebrates his 25th birthday on Friday, sustained the problem in Eindhoven ahead of the French champions' UEFA Champions League quarter-final second leg against PSV Eindhoven at the Philips stadium on Wednesday night. The initial diagnosis from Lyon's medical team is that the strain could keep Frau sidelined for up to six weeks.
Frau, who joined Paul Le Guen's side from FC Sochaux-Montbéliard last summer, has scored seven goals for his new club, including both in Saturday's 2-2 draw at FC Nantes Atlantique, a result which extended Lyon's Ligue 1 lead to 14 points. In addition, he found the net in the Champions League against Manchester United FC and Fenerbahçe SK as Lyon won Group D.
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