First choice is a bold claim to make when he has played a total of two hours of football for them and only started one game. I suspect even Deschamps isn't sure where he fits in just yet.
He can be good, have dominated an average league, and still have question marks over how well and/or quickly he will adapt here.
To be honest, I'm fed up reading about him. Arteta and his handling of Saliba since they've both joined has been a joke, but he seems to have drama written all over him and he hasn't kicked a ball for us yet.