If both defenders are unavailable, Wenger will have to turn to back-up options Per Mertesacker and Rob Holding to fill the void, as Calum Chambers also remains sidelined with a hip injury. He trained on his own and the first signs are positive.
The Gunners will keep a close eye on forward Alexis Sanchez as he has had a long trek back to London following Chile's final World Cup qualifier against Brazil, which saw them lose 3-0 in Sao Paulo and miss out on a place in Russian Federation next summer as a result.
Wenger said: "We will assess Sanchez when he comes back, I watched the Brazil game and he got some special treatment in that game".
Wenger said contract talks with German global Ozil, who is in the final year of his deal, were progressing well. "It looks like if he survives the test he is capable to play".
The Blues are away to Crystal Palace, yet to even score in their seven successive defeats this season let alone take any points, while the Gunners make the short trip to Watford in their match.
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