Arsenal apparently fear that they could be without leading striker Olivier Giroud for up to three months.
The Frenchman injured his foot while blocking a clearance from Sylvain Distin moments after scoring a late equaliser in the 2-2 draw with Everton on Saturday.
He will definitely miss the second leg of their Champions League qualifier against Besiktas on Tuesday and the Premier League trip to Leicester City this weekend, and medical staff at the Emirates Stadium are believed to be concerned that the 27-year-old could face a lengthy layoff.
The Telegraph claims that the Gunners are waiting to learn the results of a second scan which will reveal whether Giroud has broken his ankle, with swelling to the area making an immediate diagnosis difficult.
Should Giroud be sidelined, manager Arsene Wenger would be left with Yaya Sanogo and Joel Campbell as his only recognised forwards, and could reportedly be forced back into the transfer market to recruit cover.