Reiss Nelson is set to miss up to two weeks of action after pulling out of the England Under-21 squad.
The Arsenal winger had been called-up by Aidy Boothroyd for the upcoming internationals against Slovenia and Austria, but withdrew from the squad on Monday alongside Wolves' Morgan Gibbs-White and Manchester United's Mason Greenwood; who have also returned to their respective clubs with back injuries.
The trio have been replaced in the squad by Swansea City pair Sam Surridge and Ben Wilmot.
Nelson's withdrawal is a slight concern for Arsenal, but football.london reported on Monday that the the decision was precautionary more than anything else, and the winger should be in contention for the Gunners' trip to Sheffield United after the international break.
However, as reported by the Evening Standard on Tuesday morning, that's not the case unfortunately.
Nelson's knee injury is set to keep him out of action for at least a fortnight, which means he won't be available for selection until next month.
The 19-year-old has firmly established himself in Unai Emery's first team plans this season, after returning from a loan spell at Hoffenheim last campaign.
Nelson started in the 4-0 win over Standard Liege last week, but was left out of the squad entirely for the Premier League win over Bournemouth on Sunday.
Speaking after the 1-0 win over the Cherries, Unai Emery said: "We were speaking before the match about the first four matches we played, today we wanted to do one step ahead, doing better and controlling better the match but knowing it was going to be difficult.
"We controlled the first half. We played with a very good organisation, defensively very strong. We didn't concede chances.
"We scored one goal and a lot of times got into their box with possibilities to score the second goal.
"We wanted to improve in the second half. We could improve. The second half was a very good opportunity to keep our confidence, to get better with the ball, combinations and control and stopping their action with the ball.
"We did it perfectly in the first half but in the second half, maybe because the first chances arrived very early, we lost that confidence.
"We have also a lot of young players and we need to take experience, minutes and to know that difficulty inside the pitch. We know every team here is difficult here, it's the most difficult domestic competition.
"We are very happy with that result and very proud of our work and we are very critical to improve things."
