The midfielder has not played for the Gunners for almost four months with a serious thigh problem, which forced him to undergo surgery.
The injury was sustained in training, but Arteta revealed that he has suffered a setback in the same area.
Partey has not played for Arsenal since 8 October, or for anyone since 18 of the same month, and has made just five appearances for Arteta’s side this season.
"With Thomas unfortunately we had a little setback a few days ago,” Arteta said in a press conference.
He’s not going to be available in the squad for Liverpool. We don’t know if it’s a few days or weeks. He felt something in a very similar area and he wasn’t able to train the last few days.
"It is a big concern because he was such an important player for us. He was getting some momentum at the start of the season and then we lost him for a while. Now we have been a long time without him. He gives you something very different and the only one who can give you this in the squad. He’s been a real miss."
However, Gabriel Jesus has trained with the club the whole week and is likely to be fit enough to feature at the weekend.
Arsenal will travel to Anfield looking for their first win at the stadium since the 2012-13 season when Lukas Podolski and Santi Cazorla scored, in a match that pre-dated the start of Jurgen Klopp’s tenure at the club.
Since then the Reds boast a formidable record against Arsenal, having won seven and drawn seven of the last 14 meetings between the two sides in all competitions at Anfield.
But Arteta shrugged off any suggestions with a joke, saying: “They are living together now, they are best mates! You don’t argue with someone you don’t have a great relationship with. That happens because you have the trust and chemistry to react the way you did.”