I suspect that Ancelotti wants to see a lot more from him when he doesn't have the ball. His defensive stats are relatively poor (compared to the experienced PL players listed above) and maybe he needs to improve his awareness, tackling and blocking? If you are playing James, you can't really afford to have another 'luxury' winger who is not that good defending on the other side or else the midfield will be totally overrun trying to cover for them.
Despite the lack of belief in Sigurdsson, Iwobi, Gomes and Bernard, they are all experienced enough to be able to block off potential passes, occasionally nick the ball and help break down attacks, even if they are not out and out defenders.
I like him and I suspect he will make it but he maybe needs to take a good look at Richarlison and the way he plays to prove his worth to the team.