Chelsea have made no defensive signings this summer but their backline will still be radically changed. They will switch from a back three to a back four under Sarri which, in turn, changes the role of all the outfield players.
The wing-backs are converted to full-backs, which reduces their physical workload, but exposes them to more defensive responsibility. The centre-backs will get less time on the ball and have to cover more gaps between them.
Sarri is also implementing a high line and defending without the ball in a narrow shape, as he hopes intelligent pressing can get his side the ball back quickly.
David Luiz is back and seems to be a player that Sarri likes after he fell out with Conte last season, causing him to play just 17 times having been essential for the club the season before.
Antonio Rudiger looks like he will take a starting spot under Sarri to begin with, leaving the likes of Andreas Christensen and Gary Cahill on the bench. Cesar Azpilicueta was a centre-back last season under Conte, but he reverts to the right-back position in which he made his name.
Marcos Alonso is so far winning the battle with Emerson Palmieri to play at left-back, with Davide Zappacosta offering an option in both full-back positions.