Bukayo Saka started strongly against Burnley on Sunday, but he was forced off at half-time.
The 18-year-old went down after 25 minutes and, although he received treatment, he was not moving freely for the remainder of the first half.
Mikel Arteta gave an update on Saka in his press conference:
on what the injury is...
He had a knock in his knee and his hip, so we will see.
on Bukayo being missed in the second half...
He's been a threat for us and in the way we planned the game, we thought we could exploit them with him and he did really well when he was fit.