Mathieu Flamini has been ruled out of Arsenal's Champions League clash at home to Borussia Dortmund on Tuesday with concussion.

The French midfielder was forced off with the problem on Saturday during the Gunners' 4-1 win over Norwich City in the Premier League.

"Flamini is doing well but we will not play him tomorrow," manager Arsene Wenger told reporters.

Arsenal head into the match at the top of Group F following two wins from their opening two fixtures in the competition.