Its not, he shows for the ball constantly and is always looking to get involved in the play
And perhaps this comes back to something we learned at the beginning of the season about him being quite a shy character -
Now, an introverted personality type is likely going to need some kind of affirmation they're doing the right things.
Like if he's showing for the ball and he's not getting it, his type of personality is much more likely to respond with 'why me? what have I done wrong?' Same also with little things like not getting fouls and penalties that he should. 'What did I do wrong?' No doubt he'll respond to this with professionalism in training, etc - he's not going to stop showing for it, I don't think - but he's also highly unlikely to respond to it by demanding the ball (like the way Mane took it off Matip's toes tonight, the wrong decision as it happens but the kind of wrong decision that shows confidence). You can see the difference with players like VVD, Alisson, Henderson and Fabinho - more naturally extroverted and vocal, very loud in demanding the ball, not shy if they don't get it - less likely to question themselves if they're not involved in play.
It's a combination of things but it could quickly turn the other way, too - when he feels he has that trust, when he feels comfortable and that this club and this team is truly where he belongs, he'll really shine. And when teammates realise what a weapon it is to have a player who wants the ball where he's marked - indeed seeks out the tightest spaces precisely because he can use them - then what a weapon we'll have added to this team.