Chelsea announced on their official website that chief executive Peter Kenyon is leaving the club in a full-time capacity from October 31. Kenyon will continue to be a non-executive director and represent Chelsea on various Uefa and the European Clubs' Association committees.
He said: "I am extremely proud of my time at Chelsea and of the friendships I have forged with everyone here.
"I have been in football for 15 years and I can say with great certainty and pleasure the experience at Chelsea is one of the best I have had.
"When I joined Chelsea it was an incredible challenge and together with all the staff, the players, the board and Roman, I think we have really built a club, in a relatively short space of time, that can be in the forefront of European football for many years to come. That is a major achievement.
"I am also delighted that our relationship is not ending and I can continue to make a contribution to keeping Chelsea in that position and to go back to visit friends.
"I intend to take a little time off before considering what I do next but I am certain I have at least one major challenge left in me.
"I would like to wish Chelsea the best of luck for the rest of the season. I am sure Carlo can lead the team to more great things."
Chelsea chairman Bruce Buck said: "Peter has done a fantastic job for Chelsea in the last five-and-a-half years and has been absolutely central to the success on and off the field we have had during that time.
"Without his football knowledge and business acumen Chelsea would not be where we are today.
"Everyone at Chelsea thanks him for that contribution and although he will not be with us on a permanent basis he will have an important role to play as a non-executive director and in the various roles he holds in European football bodies.
"When Peter first joined us we knew we were recruiting a top executive from business generally, not just football. With that always came a certain inevitability he would eventually want to seek a new challenge and I am sure that is what he will do.
"Whatever his next permanent job we wish him the best of luck in the future. He will always be welcome back at Chelsea."
