Granit Xhaka will see further knee specialists with official confirmation on his injury lay off expected within the next 24 hours, football.london understands.
The Switzerland international had to be substituted in the 82nd minute of the North London Derby after sustaining what looked like a knee injury following a collision with Tottenham midfielder Lucas Moura.
A positive Covid-19 test saw Xhaka miss Switzerland's international fixtures at the beginning of the month.
"He came back and he was fine because he really looks after himself," Arteta revealed in his pre-match press conference on Friday afternoon.
"He was training and as he always is, he gives you the maximum and the best possible attitude to compete and win matches."
Arteta made as many as 10 changes to the side that started the 3-0 Carabao Cup third-round win over AFC Wimbledon in midweek with Thomas Partey the only survivor.
Xhaka's return to the team saw the midfield dominate their opposition on Sunday afternoon, but Arteta admitted afterwards that the 28-year-old's injury is likely to be a lot worse than first feared.
"Unfortunately he got injury and I'm pretty worried because it doesn't look very positive at the moment."
Xhaka's return to the team saw the midfield dominate their opposition on Sunday afternoon, but Arteta admitted afterwards that the 28-year-old's injury is likely to be a lot worse than first feared.
"Unfortunately he got injury and I'm pretty worried because it doesn't look very positive at the moment."
