Arsenal midfielder Thomas Partey will need a scan on an ankle injury he sustained during Sunday’s 2-1 pre-season defeat by Chelsea.
Partey, 28, limped off during the first half following a tackle by Blues midfielder Ruben Loftus-Cheek.
“At the moment it’s not looking good because he was in pain and he could not continue which, for Thomas, is pretty unusual,” said manager Mikel Arteta.
Arsenal travel to Brentford in their Premier League opener on 13 August.
And Arteta has ruled out selling midfielder Granit Xhaka before the transfer window shuts at the end of this month.
The Switzerland international, who scored the equaliser against Chelsea in his first appearance of pre-season, has been heavily linked with a move to Roma.