Arsène Wenger has said that Laurent Koscielny still cannot run and will be out for at least another three or four weeks. Koscielny has not played for more than a month because of achilles trouble and the Arsenal manager added that the recovery would depend on how the central defender responded when he returned to light training.

Koscielny last played for Arsenal in the 2-0 Premier League defeat at Chelsea on 5 October and he then joined the France squad for their fixtures against Portugal and Armenia. But the French Football Federation stood him down and returned him to Arsenal, after examining his achilles tendons. They announced in a statement that Koscielny had been suffering with chronic tendinitis of both achilles tendons for several months and said that they had not noted any favourable changes.

Arsenal said at the time that the problem was not serious, that Koscielny had returned to London only as a precaution and they were hopeful that he would regain fitness in time for the league game at home to Hull City on 18 October. The estimate was later revised for the home fixture against Manchester United on 22 November and it has now been put back again. “He has not started running outside so you cannot think he will be available in two weeks’ time,” Wenger said. “Then, you have to see how he responds to going outside and running. He is not there yet anyway. He cannot run. He will not be available for three or four weeks.”

Wenger said that rest had been the only option for Koscielny and added that surgery would not be required. He also made a joke, that sounded a little curious, about the reason for the problem. “It’s just inflammation. Too much French salami,” Wenger said. “He won’t need surgery. His achilles on the scans are quite good. He could not go on, so we had no choice.”

The setback means that Wenger’s defensive resources will be stretched for a while longer. With the right-back Mathieu Debuchy out until Christmas time with ankle damage, the manager is down to four established defenders, plus the 19-year-old right-back Héctor Bellerín. Nacho Monreal has been asked to cover in central defence and the left-back has not always looked comfortable. He will face a challenge at Swansea City on Sunday against the powerful centre-forward Wilfried Bony.

The midfielder Mikel Arteta is out with a hamstring strain – he hopes to be back for the United game – while Wenger offered no clarity on the status of Abou Diaby, who is struggling with his latest muscular problem. The positive news on the injury front was that Olivier Giroud is due to return to training next week, following the fractured tibia he suffered at Everton on 23 August.

Wenger has been able to welcome back Theo Walcott to the squad after a long-term absence following cruciate knee ligament surgery in January but he warned that it would take weeks before Walcott was back to his best. The England winger returned to full training on 13 October and he enjoyed a brief cameo in the home win over Burnley last Saturday.

“Once you are back in full training, you count two months,” Wenger said. “People think you are back and you play but it’s not like that. Ten months [out] is a long time in top-level football. You lose the sharpness, the speed. At the top level, it’s a fraction of a second that makes the decisions. And it’s to find the confidence to get away from people.

“You’re nearly there and you’re not there and, for a while, you think: ’Will that ever come back?’ And suddenly, yes, it’s there again. But it takes time to get that fraction of pace. Theo will go away with England [next week] and he will get competitive training every day, and get back into games. Maybe he can play against Scotland [on Tuesday week] and gain a lot from that.”