Martin Keown believes that John Terry has been displaced as the main defender at the club by Gary Cahill.
Terry will be forever remembered as a Chelsea legend and he has been a major part of their team for the past decade, but Keown feels that Cahill has overtaken him in the selection order now.
Although the former Arsenal defender admits that Terry will play when he is fit, he believes that he is now Jose Mourinho's second choice in the pecking order at centre-back because of the form of Cahill.
"I think Chelsea are changing the guard and Cahill is now the key man in their defence," Keown said to the Daily Mail. "He is quicker and more mobile than John Terry. He is making more and more vital interceptions and I think he just about tips the balance in that defence.
"Terry is in fantastic form but Chelsea are aiming high. You look at what happened to Petr Cech with Thibaut Courtois replacing him and you know they are a club not afraid to make tough decisions. But Cahill has learned a lot from Terry and is a late developer in a way.
"He strikes me as somebody who has to believe in himself to take challenges on but now he is getting that confidence from Mourinho. If anybody has to play three games in a week, it’s him."
There were a number of doubters over Cahill's ability when he was signed from Bolton Wanderers, but he has developed hugely since a move to Stamford Bridge.
A towering defender, Cahill is also blessed with decent technical ability and he has also matched that with his pace.
The 28-year-old has the speed to cover for Terry and the two have made a formidable partnership at the heart of Chelsea's defence.
It has been the more attacking members of Mourinho's squad who have picked up the majority of the plaudits this season, but their success wouldn't have been possible without their back-line proving so resolute.
Chelsea are already four points clear of at the top of the Premier League - and six points ahead of Manchester City - and they will be determined to ensure they build upon this gap in the coming weeks.