Santi Cazorla has damaged the ligaments in a knee, which has added to the sense of worry over his fitness prospects, although Arsenal are still unclear as to the precise time-frame for his absence.

The midfielder was hurt in the 46th minute at Norwich City on Sunday, when he appeared to jar the joint in a coming-together with Gary O’Neil, and Arsène Wenger, the manager, did not know afterwards whether the ligament had been affected or if it was a kick to the nerve.

It has now been confirmed that the problem relates to the ligament and Arsenal are continuing to assess the fall-out. Cazorla has already been ruled out of Saturday’s Premier League game at home to Sunderland and next Wednesday’s decisive Champions League tie at Olympiakos, and it would be a surprise if he were not out for longer.

Cazorla went on to complete the 90 minutes against Norwich, although he finished as a virtual passenger and only stayed on because Wenger had used his three substitutes. “The worrying thing was that it got worse,” Wenger said after the game.

Arsenal are also still assessing Alexis Sánchez, who injured a hamstring in the same game, with the initial indications being that he is likely to be out for three to four weeks. The damage to Laurent Koscielny’s hip is not as serious as was first feared and he may even feature against Sunderland.