Olivier Giroud will miss both of Arsenal’s remaining Champions League group matches after the club made the mistake of not including the striker on their original squad list.
Giroud injured his ankle on August 23 and was not expected to return until January, after all the group fixtures had taken place.
Clubs can only register 25 players on an ‘A List’ for the Champions League group matches, which must be submitted by September 2 and include eight home-grown players.
Arsenal need just one point from their remaining two games to qualify for the knock-out stages and France international striker Giroud could be included for the rest of the competition, with the next squad list due by February 3.