1) Willian
With the arrival of Maurizio Sarri, Chelsea fans were highly optimistic that the attacking threat they possessed would be used in a more positive way as compared to under their previous manager Antonio Conte.
However, the Blues have failed to capitalize on their blistering start to the 2018-19 campaign. Willian has been out of form for the majority of this season, failing to offer anything to the team on either the attacking or the defensive end.
Most fans would say that Alvaro Morata hasn't been a threat either, but it needs to be noted that Morata has been injured and hasn't featured for Chelsea as extensively this season. 835 minutes for 5 goals doesn't seem so bad!
On the other hand, Willian has been sloppy, giving away the ball easily in essential attacking phases and also losing the ball in the one-on-one duels with opposition players.
Chelsea need to look into their vastly talented youth setup and select someone like Callum Hudson-Odoi to replace Willian.