Roy Hodgson must decide early next week whether to risk the likes of Steven Gerrard and Jamie Carragher in Liverpool's opening Europa League qualifier.
The inspirational pair, along with fellow England player Glen Johnson and Denmark's Daniel Agger, have only been back in training a week after the World Cup delayed their summer breaks.
They have also been working back on Merseyside while Hodgson and most of the squad have been at a training camp in Switzerland.
As a consequence, Hodgson is unsure whether any of them will be ready to be thrown into competitive action in Thursday's Europa League third qualifying round first leg against FK Rabotnicki in Macedonia.
Hodgson is already deprived of the services of Fernando Torres, Jose Reina and Dirk Kuyt, who all reached the World Cup final.
The game comes 18 days before the Reds' Premier League opener against Arsenal at Anfield on August 15.
The 62-year-old said: "It's a very difficult decision because, one, it's a question of what levels people have reached and, two, the effect it will have on the future by putting them into games early when maybe they haven't reached the right level of fitness.
"These matches are important if you want to continue in the Europa League and we've got to be very careful that we don't therefore use players that the sports science team are convinced are not ready to take part.
"If we did that, then come August 14 or the middle of September or October, we could suddenly find ourselves with a lot of injuries and really struggling to get points in the Premier League."
Hodgson has recent experience of successfully steering a side through such early challenges.
His old Fulham team entered the competition at the same stage last season and went on to reach the final.
The return leg of the tie takes place the following week, on August 5.
Meanwhile, Hodgson offloaded Albert Riera, who ended his unhappy spell on Merseyside by signing for Greek club Olympiakos.
The 28-year-old winger went from one extreme to the other as, after falling out of favour at Anfield, jubilant fans lined the streets to greet him in Athens.
Riera was frozen out at Liverpool after launching an outspoken attack on previous boss Rafael Benitez and then describing the club as a "sinking ship".
On his extraordinary reception, the Spaniard said: "I did not expect so many people, honestly. It was a surprise for me."