Thomas Vermaelen is back in full training with Arsenal but the club are still waiting to discover the full extent of Carl Jenkinson's knee injury.
Belgium centre-back Vermaelen has endured a testing time over the past 12 months, missing a huge chunk of last season following an Achilles operation on his right ankle.
The 25-year-old was then forced to undergo a procedure on his left ankle in early September, when it was initially expected he would return to action within a month.
That prognosis has proved to be overly optimistic for a player whose absence has been sorely felt, but Arsene Wenger hopes to have the imposing defender back for the home date with West Brom on 5th November, with midfielder Abou Diaby making similar progress from his own ankle operation.
Wenger told the club's official website: "Vermaelen will be back in full training on Friday. It is 10 days to two weeks for him.
"Diaby is getting better but is not available to play yet. He's probably back in around two weeks - he is just a fraction behind Vermaelen."
Full-back Jenkinson limped out of the midweek UEFA Champions League victory over Marseille with a knee problem and is due to undergo a scan with the Gunners boss still to be given the complete prognosis.
Wenger added: "We don't know yet but it is very unlikely he will be available for Sunday. He is having a scan and we will know some time on Friday."
Deadline-day signing Per Mertesacker has been thrust into the action immediately due to the Gunners' shortage of options at the back.
The £8million arrival from Werder Bremen has looked shaky at times, particularly when coming to terms with the pace of the Premier League.
But Wenger believes he is now getting to grips with life in England after a baptism of fire and believes the Germany international can be a key figure at both ends of the field.
The French tactician told Sky Sports News: "I brought him here because I feel he is a good player. He is a good organiser as well, he understands the game.
"Physically, he is getting sharper and sharper in every game. He had no real preparation for the season. We look less nervous at the back and I think he contributes to that.
"I expect from him some goals from offensive set pieces. Against Marseille we had nine corners and from that you expect to be a bit more dangerous."