Arsenal fear kicking off their Champions League tilt without Robin van Persie.
Van Persie could miss their first three Champions League group games.
And the Dutch ace is also out of the October 3 trip to Chelsea after learning his ankle injury is worse than feared.
Van Persie, 27, had hoped to be back inside a month after he was crocked at Blackburn on August 28.
But boss Arsene Wenger has been told the striker will not return until mid-October, ruling him out of Euro games at home to Braga and Shakhtar Donetsk plus Gunners' trip to Partizan.