England manager Gareth Southgate said the Manchester United players who are currently out of the squad have a "lot to do" to get back into the frame for the World Cup.
While left back Luke Shaw is out injured, Marcus Rashford and Jadon Sancho have not been selected due to poor form, leaving Harry Maguire as the only United player in the squad for their Nations League game against Hungary on Tuesday.
Rashford and Sancho have been out of favour since England's defeat by Italy in the European Championship final last year but Southgate said last month they still had enough club matches remaining to show their quality and change his mind before the World Cup in November.
Both forwards were missing from United's last three Premier League matches of the season as the club finished sixth, missing out on Champions League qualification.
When asked if United's players would be fresher in the coming season without Champions League football to contend with, Southgate told reporters, "we've only got one with us. They've got a lot to do to get back in the squad.
"I think the lower the load then of course the less likely for injuries and the hope that players can be that little bit sharper but there's no way of knowing. Some players are at their best when they're in a rhythm of playing."