Kieran Tierney has been taken to a London hospital to diagnose the extent of the shoulder injury he sustained in Arsenal's 3-1 win at home to West Ham United.
Speaking at the end of his post-match press conference Freddie Ljungberg, the Arsenal interim head coach, said that it was too early to confirm the extent of the injury.
The Swede did, however, suggest that the decision to take Hector Bellerin out of the starting line-up minutes before kick-off was a precaution after the full back felt a tweak in his hamstring.
"Hector had a feeling in his hamstring during the warm-up and we took the decision. Not going to force anyone to play if they don't feel 100%," Ljungberg said.
"It was a straight swap on that with Ainsley. Ainsley has been out in the cold a little bit but came in and did really well. I'm really proud of him."
On Tierney, he added: "It's something with his shoulder but I don't know exactly what that is. We obviously had to take him off. He's going to hospital to get it checked."
Although Arsenal failed to produce a shot on target in the opening hour, three goals in nine minutes turned the game around and Ljungberg hopes it can have a transformative effect on players who have been short of confidence.
"The main thing is we can't get carried away," he added. "We have a lot of things to work on but it felt nice to win.
"It's been hard on the players but I thought 'give it a go in the second half.' And they did that. It was amazing to see. We saw West Ham getting a bit tired around the 60th minute and we sliced them open.
"We played some really good football in my opinion, that's how we want to play."
