Besides Havertz, stars like Gabriel Jesus, Bukayo Saka, and Gabriel Martinelli are also on the injury list ahead of the weekend's match against Leicester and for a longer period ahead.
The number of matches in the tight schedule is considered by Arteta to be a cause.
We can't prove it, but it's inevitable that it's due to the number of played minutes, he says at a press conference.
We have injured players who over the last two seasons have played 130 matches. In the end, an accident is bound to happen. But we train less than ever.
The London club is second in the Premier League ahead of the weekend's round, seven points behind Liverpool.
A few places behind are Manchester City and Newcastle, two teams that meet on Saturday. Alexander Isak has gone goalless in the last three matches ahead of the meeting with Norwegian goal king Erling Haaland.
