There were rumblings early on in the season about him and Varane being unhappy with Ten Hag and the tactics. If that's the case, he's not wrong, but I feel like he's checked out and doesn't give a shit at this point.
He'd probably still have been very useful playing in the more compact type of midfield we had last year, but never had a chance covering the acres we're asking from our one-man midfield setup now (nor as a CB trying to cover wide areas as we saw today).
Looks like he's running on a crosstrainer, and it's like we're set up to highlight that weakness as much as possible.