Arsenal manager Mikel Arteta has revealed that attacker Reiss Nelson will take "a few weeks" to recover from the injury he sustained against Juventus in last weekend's friendly.
Lightning has unfortunately struck twice in friendly matches for the 22-year-old, who missed the start of the season after sustaining a serious quadriceps injury over the summer.
Nelson has since recovered from that issue and has forced his way back into Arteta's plans, playing a prominent role in December's mid-season exhibition matches during Bukayo Saka and Gabriel Martinelli's time at the World Cup.
Arsenal rounded off their friendly period with a 2-0 defeat to Juventus at the Emirates last Saturday, but the game was marred by an injury sustained to Nelson during the first half.
The former Feyenoord loanee went down holding the back of his thigh and had to be withdrawn, and Arteta admitted at the time that Nelson's issue did not look good.
Addressing the media ahead of Arsenal's return to Premier League action against West Ham United on Boxing Day, Arteta conceded that Nelson would spend a number of weeks out of action, but Emile Smith Rowe is edging closer to a return from groin surgery.
Meanwhile, Gabriel Jesus is expected to remain out until March after undergoing knee surgery, but Arteta refused to put any pressure on the 25-year-old to come back at a certain point.
"With Gabi it's difficult to put a time frame because it was a significant injury. Knowing him, I prefer not to give any dates," Arteta told reporters at his pre-match press conference.
"Emile is close. He had a setback but he's there and he's in a good place. With Reiss, unfortunately he picked an injury against Juventus and he's going to be out for a while I think.
"I'm talking weeks not days. He will be out for a few weeks. Let's see how he reacts in the next few days. He felt something straight away and with sprinters that's not a good sign."
Nelson has two goals and three assists from seven games in an Arsenal shirt this season, bagging a brace and setting up Thomas Partey's strike off the bench against Nottingham Forest in the top flight on October 30.
With Jesus and Nelson both sidelined, Arsenal are widely expected to enter the transfer market for a new attacker in January, with Shakhtar Donetsk's Mykhaylo Mudryk believed to be the priority target.
Arteta reaffirmed that the Gunners would look for opportunities to improve the squad in January, adding: "We're will be in the market always active and we will assess the biggest opportunities that we have.
"We are going to be active and active means we are looking to strengthen the team. This squad still doesn't have the luxury of not maximising every single window. We have to do that because it's really important. But then we have to get the right profile, it has to be the right player to take us to the next level."
Arteta was also asked for an update on the contract situation of Martinelli, who is supposedly on the brink of agreeing a new £200,000-a-week deal in North London, but the Spaniard unsurprisingly remained tight-lipped.
"No news. Extremely happy with him. He had a great experience with the Brazil team. You can keep asking me in the coming weeks," Arteta responded.
Arsenal resume domestic duties five points clear of Manchester City at the top of the Premier League table - the first time since the 2007-08 season that they have occupied first place at Christmas.
