Chelsea midfielder Michael Ballack is unlikely to make his Premier League debut this weekend as he has failed to recover from a hip injury.
The German skipper, who joined the English champions on a free transfer in May, picked up a the knock during the 2-1 Community Shield defeat by Liverpool last week.
“My opinion is that Michael will not be fit to play,” Chelsea boss Jose Mourinho told reporters.
“His improvement since last Sunday has been very small and has not trained with the team.
“He trained on his own on Thursday so I don’t believe he can play unless he improves a lot.
“The objective from the beginning was to play Ballack and (Frank) Lampard together but we have not had many chances to work on it.”
Mourinho said his side were not ready for the start of the new season as their preparations have been hit by players returning late from World Cup duty.
“I like to play competitive matches but only when I feel my team is ready for them and that is not the case,” Mourinho said.
“As a result of that I feel the challenge is bigger. It is a funny situation because I am having to prepare a team without any matches.
“When you start pre-season you need a minimum of a month to get your team ready.
“You need your body to re-adapt to train in the first week and then work properly to improve your physical and tactical areas.
“We will only have 15 players for the first game… it is a difficult situation for us.
“Since I arrived at the club, we have won the opening matches 1-0 over the last two seasons. They were both difficult matches but I hope we can do it again.”