Borussia Dortmund will be without their captain Sebastian Kehl for the game against Napoli on Wednesday.
Last year’s Champions League runners-up face the Partenopei at Stadio San Paolo in their first group stage match of the campaign.
But they will do so without their influential leader, who misses the match with ligament damage in his foot.
A statement on the club’s website read: “A scan performed by team doctor Markus Braun confirmed damage. Kehl will therefore stay out of action for six weeks.”