#1 Kurt Zouma
The Frenchman might have been a part of Chelsea's first team, had it not been for that unfortunate injury against Manchester United two seasons ago. He was a regular under Jose Mourinho as well as Guus Hiddink till 2016.
He is currently on loan at Everton where he has given very commanding displays. The former Stoke City defender is blessed with pace and good aerial ability.
Chelsea defenders have often struggled when exposed to pace, while Zouma should thrive under Sarri when they face counterattacks. He has plenty of experience as he has already made 70 appearances for the Blues.
The former Saint-Étienne defender has shown that he has what it takes to play at the top level. It was only because of the long term injury that his career got got temporarily derailed. The Blues must consider how good he was in the past for them and could include him in their plans for next season.