Arsenal midfielder Thomas Partey was forced off injured during first-half stoppage time of his side's Premier League defeat against Tottenham.
Partey returned from a thigh injury to make his first appearance for the Gunners in over a month when he was named in the starting XI for the north London derby on Sunday.
He walked over to the touchline during the build-up to Harry Kane's goal that put Spurs two goals up and was replaced by Dani Ceballos immediately after and just seconds before half-time. Spurs would go on to win the derby 2-0, returning to first place in the Premier League.
After the match Arsenal boss Mikel Arteta confirmed Party would have an MRI, saying he appeared to aggravate his previous injury.
"I applaud their first goal, it is world class, but the second goal we are a man down, we leave a massive gap and they take advantage," Arteta told the BBC.
"He [Thomas Partey] has to stay on the pitch. It looks like the same injury he has already had, he will have an MRI."
Partey had been out of action since he was taken off in his side's 3-0 defeat at home to Aston Villa on November 8 and subsequently missed Premier League matches against Leeds and Wolves as well as the Europa League encounters against Molde and Rapid Vienna.
The Ghana international only returned to Arsenal training during the week and Arteta said after his side's win against Rapid Vienna that the summer signing could feature against their city rivals.
Ahead of the game on Sunday, Arteta was asked about the 27-year-old's inclusion in his starting XI.
He told Sky Sports: "We didn't expect him to be fit for the game but he has been training well and [is] ready to play."
Arsenal fell behind just 13 minutes into the match at Tottenham Hotspur Stadium. Son Heung-min led Spurs' charge forward, combining with striker Kane before lashing past Bernd Leno from outside the box.
Son then turned provider as he passed to Kane who then fired in to double the home side's advantage, which would be the game's final goal.