Arsenal forward Kai Havertz is understood to be facing a spell on the sidelines until early to mid-January following a complication he suffered last month during his rehabilitation from minor knee surgery. The striker has been unavailable since picking up a knee injury against Manchester United in the Gunners' opening Premier League fixture of the campaign on August 17.

This required Havertz to undergo knee surgery a week afterwards. According to the Daily Mail, in November, the 26-year-old was within a week of returning to the matchday squad before experiencing a setback in his final training sessions.

Whilst the German now anticipates being available for matchday squad selection by the middle of next month, he has not returned to training since his complication. There is now understood to be a chance that Havertz could feature in the Arsenal squad for their league fixture against Liverpool on January 8, though it's more probable he will be back for the FA Cup third-round tie against Portsmouth three days afterwards.

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Havertz has endured an injury-hit year, having torn his hamstring during the north London club's warm-weather training camp in February last season. When questioned about Havertz's injury earlier this month, Arteta said: "Matter of weeks. Let's see how it evolves in the next few weeks. He's doing really well, he's doing stuff on the pitch, but I think he needs some time."

The development will concern Arsenal's manager, as Viktor Gyokeres has had a difficult start to life at the club. The striker has managed only six goals this season following his £63.5million summer transfer to the Emirates Stadium.

Arteta has recently urged critics to 'leave him alone' - whilst acknowledging the forward needs to find the net more regularly. He said: "There was a lot of excitement because we were bringing a proven scorer that had probably the best stats in Europe.

"He is a player that comes to a different league, the most demanding league in the world, and what happens if he doesn't score for five or six games?"

"That was my only question to him: 'How are you going to react if you don't score in five or six games? Can you cope with that? And then what's going to happen in the next 100 games?'".

"And that's what you have to see. The sample is very small.

"So, leave him alone, let him do what he does best, be behind him and I'm sure things will turn out in the right way."

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