The Norwegian missed the first leg of the tie, which Arsenal drew 1-1 at Emirates Stadium, due to an ankle issue picked up while on international duty.
Odegaard, who is currently on loan at Arsenal from Real Madrid, now looks set to miss the Gunners’ trip to Sheffield United on Sunday – and possibly the second leg of their tie with Slavia on Thursday.
Asked if he was concerned Odegaard might be missing for the long term, Arteta said: “We don’t know.
“He wasn’t able to play today and he will be out, I think, for the next game or two. But we don’t know yet.”
Odegaard has been one of Arsenal’s bright sparks recently and was named the clubs’ player of the month for March after scoring in the north London derby win over Tottenham.