The Norwegian set an unwanted record by becoming the first player in Premier League history to be substituted before half-time in three consecutive starts.
Martin Odegaard also came off in victories against Leeds and Nottingham Forest due to a shoulder problem. The 26-year-old appeared over that after his eye-catching display in the Gunners' 2-0 Champions League win over Olympiakos in midweek.
But he had to be withdrawn again on the half hour mark at the Emirates after colliding knees with West Ham's Crysencio Summerville. "I think he had a clash, knee-to-knee and immediately he was uncomfortable. I just spoke to him and he is not positive about it," said Arteta, who revealed Odegaard was in a knee brace after the match. "Let's wait and hopefully it is not that bad."
Otherwise Arteta was able to enjoy his 300th match in charge as Arsenal moved a point clear of Liverpool.