Arsenal have been dealt a fresh injury blow ahead of Saturday’s trip to take on Stoke City, with Nacho Monreal ruled out with an ankle injury and Laurent Koscielny a doubt with his ongoing Achilles problem. Arsene Wenger’s men recorded their third successive win against Southampton on Wednesday evening, but it came at the expense of yet more casualties in what has been a season blighted by injuries for the Gunners.

“We have to assess a few players today because we had some bad surprises with Monreal being out for tomorrow’s game.” Wenger said at his pre-match press conference on Friday. “It’s a torn ankle in the first minute of the [Southampton] game. If you watch the game again, you will see his ankle twisting very badly. But he was tough enough to stay on. He had a scan last night, I haven’t got the result yet. It could be a few weeks out.”

Wenger is hopeful that Kieran Gibbs will be fit to take Monreal’s place at left-back at the Britannia Stadium following the England international’s own recent injury problem. But a defense, after much early season difficulty, that has kept three clean sheets could be further reshuffled depending on the fitness of Koscielny. After two months out with a long-term Achilles complaint, the center-back has made an immediate impression on his return in the last two matches. Yet, Wenger cautioned that he has to be managed carefully.

“I would like him to play a third one because he is a very important player in our squad and ideally I hope he will be available for tomorrow,” Wenger explained. “But certainly that decision will only be made tomorrow morning. The problem when he plays is that the inflammation comes back.”

Yaya Sanogo and Tomas Rosicky are set to be missing on Saturday, but there is at least some positive news emanating from Arsenal’s perennially overflowing treatment room. Wojciech Szczesny was expected to be back in full training on Friday, although Wenger remained unsure whether the Polish stopper would be ready to take the gloves back from Emiliano Martinez on Saturday. The trip to the Potteries will definitely come too soon for right-back Mathieu Debuchy, although the summer arrival from Newcastle has also returned to training after nearly three months out following ankle surgery.

“Debuchy is back in training,” Wenger confirmed. “He’s short to play. The earliest he could be available maybe is Tuesday [against Galatasaray]. I don’t know whether I will take him or not because we are very short number-wise.

“The hardest part is when a player has been out for three months is to decide do you put him in straight away and risk that he has a big setback or do you wait one more week. But you have the urgency of the result that is of course very big. And therefore you have to take a calculated gamble.”

Wenger also faces a dilemma over how much to risk the fitness of Alexis Sanchez. The Chilean forward has made a sensational impact since his summer transfer from Barcelona, with his late winner against Southampton taking is goal tally to 13. But while he is key to Arsenal’s hopes of improving on their current sixth position in the Premier League table, Wenger conceded Sanchez’s heavy schedule is taking a toll.

“He is in the red zone, you can see that when he plays, but he can dig deep,” Wenger said. “I think he played his 27th game on Wednesday since the start of the season. Unfortunately you never know how far you can push. We are not scientific enough today to predict that completely, but he has great recovery potential. He recovers very quickly and he is always sharp and wanting to play.”

With Arsenal having secured qualification for the last 16 of the Champions League and only having an outside chance of overhauling Borussia Dortmund for top spot in their group, Tuesday’s trip to Turkey would appear a likelier fixture than the clash with Stoke for the likes of Sanchez to be given a breather.

Theo Walcott will be forced to sit out both of Arsenal’s next two fixtures, however, as he continues his recovery from a groin problem suffered on international duty last month.

“Walcott is still struggling with his groin inflammation,” Wenger said. “I think he has an injection today to take care of that and hopefully he could be available after that. Galatasaray is too early for him.”

Walcott’s injury came just weeks after he had returned from nine months out with a torn cruciate knee ligament. And it has been a similar scenario for the Arsenal player who has been blighted by injuries more than any other in recent seasons, Abou Diaby.

“Abou Diaby is just on the fringe of coming back into full training, but he’s not there yet,” Wenger added. “He has a calf problem. He’s injuries are never severe but little grade one. He’s not available yet.”