The fact that there’s precedence for Havertz playing at 8, and there isn’t for Arteta changing up his beloved system
Don’t get me wrong, I’d love it if we did (although as I’ve said I think Rice would have been better starting than Partey in this instance) but Arteta strikes me as too much of a control freak to let go and change things up so drastically in the middle of the season (especially when only a week ago he refused to bring on any extra attackers against Everton and made like for like subs)