Gervinho blow for Gunners
Arsenal winger Gervinho is expected to be out for around three weeks with an ankle problem, manager Arsene Wenger confirmed on Thursday morning.
The Ivory Coast international had to be substituted following an awkward fall after coming on during the second half of last weekend's 1-0 win over QPR at Emirates Stadium.
"Compared to last week Gervinho is of course out, for we think three weeks," he said.
"We have no comebacks, no Wojciech [Szczesny], no [Kieran] Gibbs, no [Abou] Diaby of course as well.
"Basically the squad should be approximately the squad we had last week. We have no injuries as well from Tuesday night."
Arsenal head to Schalke for a Champions League tie on Tuesday night, so Wenger will take that into consideration ahead of the United game.
"Some players still have heavy legs, but hopefully they will have recovered by Saturday," he said.
"We play Tuesday again so I will consider the global situation - some players will be available maybe more for Tuesday than Saturday."