Tomas Rosicky has been ruled out for another month after suffering a new injury during his comeback appearance on Saturday.
The Czech midfielder made his first appearance of the season yesterday when he came on for the final stages of the Gunners' 2-1 win over Championship side Burnley in the FA Cup but suffered a muscular injury to his upper leg.
Rosicky will undergo tests to determine the extent of the problem on Sunday, although he is expected to miss anywhere from four to six weeks as he recovers.
Arsenal are already without the services of Jack Wilshere and Santi Cazorla in the middle of the park, although they have been boosted by the returns of Alexis Sanchez and Francis Coquelin, as well as the signing of Mohamed Elneny, in recent weeks.
Rosicky is now on the sidelines through injury for the 37th time in his 10-year Arsenal career.