Well, when it comes to these things it is always subjective but if you want something more concrete...On what are you basing this
He came back from the pre-season with covid and then in his first few games he lacked the normally flawless timing. In his six first games after coming back, he picked up four yellow cards - two more than he picked up in the entirety of the rest of the season. I think if you read the player rating threads from back then, you'll find quite a few noticing he wasn't in top form. Very poor against Everton and despite two wins he was struggling against both Brentford and Leicester.
Turned it around quickly though.