Just as they were looking set to mount a concerted challenge for their first Premier League title in 12 years, Arsenal have suffered an all-too familiar injury crisis that severely threatens their ambitions. Already the list of absentees was a long one, before their predicament took a dramatic turn for the worse on Saturday. Arsene Wenger’s side went down to a 2-1 defeat at West Brom, but arguably far more threatening to their hopes was an injury that struck down Francis Coquelin.

While nobody could make a creditable claim that Coquelin is the best player in Arsenal’s squad, there is a strong argument to be made that he is the most important. Wenger’s failure to sign a defensive midfielder in the summer left the club heavily reliant on a player yet to complete a full season in the Premier League and who up until last December was on loan at Championship outfit Charlton Athletic. Now he is set to miss a significant chunk of the season, including the hectic Christmas period.

“It is at least two months,” Wenger said at a press conference ahead of Tuesday’s Champions League encounter against Dinamo Zagreb. “But I’m a bit cautious. We’ve had so many bad surprises on the scans that I do not want to speculate more than that. But certainly the next two months we play without Coquelin.”

When Coquelin left the field in the early stages of Saturday it was soon clear how reliant Arsenal are on his ability to break up play. His replacement, Mikel Arteta, conceded a free-kick from which West Brom scored their opening goal, before scoring an own goal to hand them victory. Arteta is now injured, too, although Wenger remains hopeful that he has the in-house solutions to his midfield problems.

“We have players who play in this position, like [Mathieu] Flamini. We have players who can play in that position, like [Calum] Chambers, because he has been educated as a central midfielder. So sometimes this is a good opportunity for other players to turn up and show that they can do the job.”

Still, Wenger did suggest he might have to address the situation when the transfer window reopens. “I’ll do what’s needed in January even though in January it is not an ideal transfer market,” he said.

Signing a player of quality certainly promises to be more difficult in January than it would have been in the summer. Here’s a look at three players Wenger may pursue.

Grzegorz Krychowiak (Sevilla)

There were strong rumors in the summer that Arsenal were ready to meet the 30 million euros (£21 million) release clause for the Poland international. The 25-year-old played an influential role in Sevilla’s run to the Europa League title and has the tenacious skills in front of the back four that could be a major benefit to the Gunners. However, Krychowiak eventually posted on social media that he was staying at Sevilla for the coming season, and in November he signed a new contract with an increased release clause of 45 million euros (£32 million). It is hard to see Arsenal paying that figure, and they would certainly lose face by doing so, but desperation may kick in.

William Carvalho (Sporting Lisbon)

The Portuguese rising star was voted player of the tournament in the summer’s European Under-21 Championship and is thought to have been on Arsenal’s radar for some time. And the feeling appears to be mutual, with Carvalho revealing in October that he has a big fan of the Premier League, and Arsenal is the club he has the most affection for. Still, he added that he was currently content at Sporting, and, given the player also having a release clause of 45 million euros, he may not be easy to lure away, especially in middle of a season in which Sporting are currently leading the Portuguese Primeira Liga.

Lars Bender (Bayer Leverkusen)

Bender is another holding midfielder to have long been linked with Arsenal. Indeed, it has been reported that they had a bid rejected for the Germany international as long ago as the summer of 2013. The speculation has rarely abated since then, although he has continued to show his commitment to Bayer Leverkusen and was made captain of the Bundesliga club this summer. Also potentially counting against the chances of a move is the fact that Bender remains in with a strong chance of advancing with Leverkusen into the Champions League knockout phase. He may be unwilling to give that up.