Mikel Arteta insists Arsenal are prepared to dip into the transfer market in January if his squad remains as “exposed” as in recent weeks.

The Gunners have fared better than some of their Premier League rivals in terms of injuries but are without five players for Thursday’s London derby at home to West Ham.

Thomas Partey, Jurrien Timber, Fabio Vieira and Takehiro Tomiyasu are all still sidelined while Kai Havertz is banned having collected five yellow cards.

Arsenal invested over £200million on new recruits in the summer, including the £105million club-record signing of Declan Rice from the Hammers.

The England midfielder was joined at the Emirates Stadium by Havertz and Timber as Arsenal spent big having missed out on the title despite being top for 248 days last season.

With Arteta unsure of return dates for his injured quartet and the festive fixture schedule testing any squad in the division – the Spaniard confirmed Arsenal do have plans should they feel the need to act in January.

“At the moment, it is very difficult. We are really short,” he said.

“We have positions that we have been very exposed for the last six weeks and hopefully we are going to get players back. In what condition and when?

“That’s a question mark and as well because we have some long-term injuries still for certain players that give us a lot of versatility and that’s an issue.

“We have certain targets, ideas if things happen. As well, we don’t know how the squad is going to look in two weeks’ time and you have to be always prepared for that.

“But it is a very, very tricky market that shifts very quickly and it is quite unpredictable as well – and you have to be prepared. We will be prepared and we will try to make the right calls.

“If there is something that we can (do to) improve the squad and that needs appear, and we cannot fulfil it with players here, we are always going to be open to do that because we want to be stronger.”

Mikel Arteta has not ruled out returning to the transfer market as he expects Arsenal to be without Jurrien Timber for the season after the summer signing suffered a knee injury against Nottingham Forest.

It was confirmed earlier in the week that Dutch defender Timber will go under the knife after tests showed ligament damage – with Arteta also insisting the number of serious injuries suffered so early into the campaign is a “big worry” for player welfare.

Timber limped out of Saturday’s 2-1 Premier League win over Forest on Saturday, with the club confirming on Wednesday he suffered ligament damage.

The PA news agency understands Timber felt no immediate pain after a challenge with Brennan Johnson just before half-time and underwent stringent tests during the interval.

Club medical staff believe the outcome of the injury would not have changed had he been substituted immediately instead of playing on for five minutes of the second half before being replaced by Takehiro Tomiyasu.

Asked about Timber’s situation, Arteta said: “Huge blow. Especially for him after just joining the club. To have the injury he has is a huge blow.

“It is for the team because we recruited him with clear intentions and what he was bringing to the team was evident and he’s not going to be able to do it this season for us. We have to adapt. These things happen unfortunately and we have to move on.

“He’s been very good to be honest. He’s a special character. He knows, he’s starting to realise the extent of the injury and the amount of time he’s going to be out. But he’s in a good place. We are willing to help him obviously and be close to him, but we know it’s going to be a long journey.”

Kieran Tierney appeared set to depart the Emirates Stadium this season but, with Timber now sidelined and Oleksandr Zinchenko struggling for fitness, the Scotland left-back could now be retained.

Arteta, too, suggested Arsenal could dip their toe back into the market following the injury setback.

“We didn’t plan with this injury. We have to assess what the options are, what are the best players that we have because, as I said, my challenge is to get the best from the players that we have. I cannot assess anyone who is not here.

“We are always open and we have to be open as well to react if something happens, not only with an injury but if something happens in the market as well. That’s what we’re doing.”

Timber was not the only player to suffer serious injury in the opening weeks of the new season, with Manchester City’s Kevin De Bruyne and Tyrone Mings of Aston Villa also forced off.

Arteta also highlighted a number of other injury issues when asked if the problems could link back to the amount of football that players are being asked to complete.

“Also Emi Buendia, (Thibaut) Courtois, it happened to (Eder) Militao as well – there is something there,” he added.

“In the past you can say: ‘yes there have been games, there have been tours as well’. But with games, tours, the World Cup in January, plus this, plus that, plus internationals. It is a lot. It is too much for the players.

“It is incredibly demanding, when you see the next 36 months of the calender for these players it is just better not to look at it because it is incredible what they are going to be doing.

“We have to look after them but, as a club, when do you look after them? To prioritise other competitions? Then we are the ones that have to look after them – what we really need is to be sitting down (discussing plans), but I think it is too late, at least for the next 36 months it is too late already.

“I don’t know who needs to raise a voice here, but there are worries, big worries on that.”

Arsenal’s season has been rocked by a serious knee injury to summer signing Jurrien Timber which will require surgery.

The Netherlands international moved to the Emirates Stadium from Ajax this summer but was forced off on his Premier League debut – Saturday’s 2-1 win over Nottingham Forest.

Timber, 22, limped off at half-time against Forest following a heavy challenge on Brennan Johnson that earned the full-back a booking.

He emerged for the second half but lasted just five minutes before going down off the ball and being replaced by Takehiro Tomiyasu.

An Arsenal statement on Wednesday read: “Further to detailed assessments with consultant specialists since Saturday, we can confirm that Jurrien has sustained an injury to his anterior cruciate ligament in his right knee.

“Jurrien will undergo surgery in the coming days and will be out of action for a period of time.

“The support and expertise from our medical team and everyone at the club will now be focussed on Jurrien’s rehabilitation programme, to ensure he recovers well and is back playing as soon as possible.”

Timber was a £38.5million signing for the Gunners and played in the Community Shield penalty shoot-out win over Manchester City before suffering the setback against Forest.

Despite losing Timber, Arsenal are still expected to allow Nuno Tavares to leave the club in the coming days, with Forest a potential destination for the former Portugal Under-21s full-back.

While signed primarily to play at right-back, Timber had started life at Arsenal on the left side of defence, filling in as Oleksandr Zinchenko recovered from a calf problem.