Arsenal will be without Olivier Giroud against Borussia Dortmund on Wednesday because the club did not register him on their Champions League squad list.
Giroud injured his ankle on 23 August and was not expected to return until late December, after the Group Stage had finished; Arsenal opted not to include him in their 25-man squad, which had to be submitted on 2 September, for the competition.
However, the Frenchman recovered faster than expected and returned to score against Manchester United on Saturday.
Arsenal face Jurgen Klopp's Dortmund needing just one point from their final two matches to qualify for the knockout stages, despite drawing at home to Anderlecht and losing to Dortmund in Germany.
Dortmund top the group despite their poor form in the Bundesliga that sees them in the relegation zone. Klopp's team have won just two of 12 matches so far in the German top flight this season.
Arsenal will be without Wojciech Szczesny, Jack Wilshere and Theo Walcott for the game, though their defensive options have been boosted with Laurent Koscielny back.
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