He has an impressive squad of talent at his disposal after signing Andriy Shevchenko and Michael Ballack in the summer.

But he fears a clean sweep of Premiership, Champions League, FA Cup and Carling Cup is still out of reach.

"My personal opinion is that you can't do it, " Mourinho said. "Because it is modern football and that means a lot of matches during the season. Modern football means an unbelievable calendar for the national teams, players from a lot of different countries, different continents, different competitions to play in and so much travelling.

"You arrive at a position where you have to make your options. You have to rotate players. You have to decide which games are more important and which competition is more important.

Mourinho launches his quest for a third successive Premiership title at home to Manchester City today and, despite his summer spending spree, the Chelsea boss finds himself short of players. Claude Makelele, Robert Huth, Petr Cech, Geremi and Joe Cole are all out and Michael Ballack is very doubtful for the opener.

Chelsea are close to adding Khalid Boulahrouz to the squad after agreeing an undisclosed fee for Hamburg's Dutch international defender on Friday. He will be the sixth summer recruit for the champions and Mourinho admits he has made changes in a bid to play in a different style.

"I wanted to change because I prefer to win 2-0 than 1-0. If you can improve that, without losing the qualities that made us champions, then you have to try to add these different qualities."

The arrival of Boulahrouz, 25, will not affect the move for Ashley Cole. "I don't think it's a secret that we feel we are waiting for one or two defenders because we don't want to lose what we've had for the last two years, " Mourinho said. "We have always had a very strong defence and whenever we've had a player out or injured we always had an answer."

FA PREMIERSHIP CHELSEA v MANCHESTER CITY Stamford Bridge, 4.00 Live, Sky Sports 1, 3.30