Chelsea captain Gary Cahill has suggested that the team have been weakened by the departure of Nemanja Matic.
The Serbian midfielder, who had two spells at Stamford Bridge, was sold to Premier League rivals Manchester United in July in a deal rumoured to cost around £40m.
Following the arrival of Tiemoue Bakayoko from AS Monaco and the consistent form of N'Golo Kante, Matic was facing a season of limited game time, but Cahill believes that he will be a big miss to the side.
"Matic is a fantastic player, a real top player. I had the benefit of realising how good he is when he's playing just in front of you, on and off the ball," Cahill told Sky Sports News during the Premier League launch.
"He's going to be a huge loss, there's no doubt about that. And for us it's important because it can be very offensive this formation.
"People look at it as a five [in defence] but really it's a three a lot of the time. The two wing-backs are pushed very high and we attack with numbers, so for us at the back in terms of balance you have to have some sort of protection and they gave us that last season."
Matic could face his former club for the first time when Chelsea and United meet at Stamford Bridge on November 4 in the league.