Marcel Desailly says Chelsea have lost an on-field manager in injured captain John Terry.
The England captain is likely facing up to a month on the sidelines, as he tries to recover from successful back surgery in France on Thursday.
Terry has already missed Chelsea's last four games with the back problem, and Chelsea legend Desailly feels his absence is a major blow for Jose Mourinho's side.
"I know the influence John has on the team," the former Nantes, Marseille and Milan defender told The Sun.
"Although Didier Drogba has been the difference in many games this season, John is probably the most important player at the club.
"He is the manager on the pitch. He's not afraid to take responsibility because he is the man.
"When the team is in trouble, he is able to lift his level and show the other players the spirit they should have.
"He knows how to correct the team when something goes wrong.
"This might even mean doing the opposite of what Mourinho has told them - but John is not afraid to do that because he's the one who sees the reality on the pitch.
"And he is very important in the dressing room. He is strong and defiant and manages to organise everything. He provides stability for the team."
Desailly thinks Terry has the capabilities of emulating the legendary career of Milan centre-back Paolo Maldini.
"I want John to reach the same level as Paolo, who I played with at AC Milan," added the France World Cup winner.
"He has been at the very top level for 20 years and John is capable of doing the same.
"I cross my fingers that he can get over this injury and go on to become the best defender in the world. I think he can do it.
"He can really be the image of Chelsea, making new players understand the spirit of the club and the story of where it has come from."