Steve McClaren has warned his England players they cannot afford to be left on the fringes of their club sides if they are to keep their place in the national team.
The England manager believes the competition is so intense that no-one can assume an England spot is automatically theirs by rights.
Of his current squad, Tottenham's Jermain Defoe and Chelsea's Shaun Wright-Phillips especially are struggling to make it into their club's first XI.
McClaren, speaking this week in Berlin where he was attending a joint FIFA/UEFA conference, said: 'I'm not going to single out one player but there are people in the squad at the moment and people we are looking at outside it.
'They have the shirt at the moment but there is competition from outside trying to get in there.
'Similarly, you pick these players on form and what I want is competition for places. I don't want anyone to join up and naturally assume that 'I'm going to play' - they have to perform.
'We have great competition for places at the present moment and nobody should feel they are assured of a place.'
Peter Crouch is another whose position is under threat following the arrival of Dirk Kuyt at Liverpool, but his England scoring record and his dedication to the national team has impressed McClaren.
He added: 'He has improved - he's always had the potential, but I think he has improved no end, developed and adapted his game in the last 12 to 18 months.
'He's always going to be a different player and that gives the team something different. I think that has proved to be case in the games that he has played. He's playing with confidence.
'We are playing Macedonia and Croatia next and we may have to use different personnel, a different formation, different tactics, in winning those games and what delights me is the way Peter Crouch has come on and proved that he is a very good player at international level.'
McClaren also expressed his satisfaction at the way his partnership with assistant head coach Terry Venables has worked out.
He said: 'After the career that Terry has had I think it takes a special kind of person to step back and take on the role that he has done, but that's the mark of the man.
'He's passionate about England, he's passionate about football and he has great experience.
'You need that experience around you and I'm in the fortunate position that he has managed around Europe and the top clubs, he has a great football brain and that can only be of benefit to me, to the players and to the team.'