The England international was substituted midway through the opening half with a hamstring injury and Arteta has now confirmed the setback.
Speaking after the game, the Spaniard said that he does not know the extent of Saka's injury, but it is not good news for the club going forward.
He said: "I don't know. He had to come off because he felt something. It is not good news obviously. We have to assess him."
Saka has been a revelation for the Gunners this campaign with nine goals and 13 assists from 24 appearances across all competitions.
He picked up two minor hamstring injuries earlier this season, but judging by his reaction today, the latest could be much more serious.
It is likely that he will be sidelined for a few weeks. Arsenal coped without him to beat Palace and will need to do the same for a while.