Arsenal forward Theo Walcott is doubtful for the midweek Europa League clash against Cologne due to illness.
The London Evening Standard says Walcott, 28, is being assessed by the Gunners' medical staff at the club's London Colney training base over whether he is fit enough to travel with the squad to Germany.
The England international has started all four of Arsenal's Europa League games this season and was expected to start at the RheinEnergieStadion.
Gunners boss Arsene Wenger is also likely to give game time to other players who did not feature in the derby win over Tottenham last weekend, with Jack Wilshere, Mathieu Debuchy and Rob Holding all in line for starts.
Arsenal have already qualified for the Europa League knockout stages but need a point to guarantee top spot in Group H.
Walcott has struggled to hold down a place in the Arsenal first team and has seen only 27 minutes of action in the Premier League this season.
The England forward has 18 months left on his contract at the Emirates Stadium, but former Gunners striker Ian Wright has urged him to move on and seek a new challenge to rejuvenate his career.
"I'm not sure where he can go now with Arsenal and he's only playing in the Carabao Cup and the Europa League," Wright told Sky Sports last month.
"He'll want to finish on a high in respect of what he's doing, he's given Arsenal great service in the time he's been there and for me he should move on for himself."
Derby County striker Darren Bent added: "He's been there for a long, long time now and I'm not quite sure how much more he can improve while he's there.
"Sometimes you can go somewhere else with new surroundings and, all of a sudden, you can kick on again. Maybe that's what he needs."