Mikel Arteta said Bukayo Saka's latest injury is "a worry" - but doesn't regret picking him to play in Arsenal's 2-1 Champions League defeat at Lens.
Saka set up Gabriel Jesus' goal, but went off with a muscular problem in the 34th minute as his side lost for the first time this season.
Saka, 22, had started his side's last two games before being withdrawn with injury concerns, and is now a doubt for Sunday's crucial Premier League game with champions Manchester City at Emirates Stadium.
But asked if he regretted picking Saka against Lens, Arsenal boss Arteta said: "No.