Speaking to reporters about Partey's condition, Arteta said: "With Thomas unfortunately we had a little setback a few days ago. He’s not going to be available in the squad. We’ll see if it’s a matter of days of weeks. But he had a little thing. I’m not a doctor, but he felt something in a very similar area and he wasn’t able to train the last few days.
"A big concern because he is 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 it has been a long time without him. He gives us something different that no other player can give us in the squad so he will be a miss."