World Cup 2018: England players must fight for place says Gareth Southgate
No England player can "safely think" they will be involved in the 2018 World Cup, manager Gareth Southgate says.
Southgate, 47, has called up three uncapped players for friendlies against Germany and Brazil in November.
He hopes to "evolve" England's style by the World Cup by using a formation with three central defenders but says no-one is guaranteed a place in his squad.
"If I had to pick tomorrow I'd know who I'd take but in the next six months it could evolve drastically," he said.
Asked how many spaces in his 23-man squad are certainties for the tournament in Russia, Southgate told BBC Sport: "I'm not certain there are many. In every position on the field there is strong competition.
"The speed of development of some of our young players and progress is eye-catching. I don't think anybody can sit and safely think they are going to be involved next summer."
'How can we evolve the team?'
Southgate has placed an emphasis on youth in his latest squad selection and believes the country's young players are clearly "hungry" given England's wins at the Under-17 and Under-20 World Cups this year.
He says he is focused on changing the way the senior team plays - with a greater focus on passing the ball through the team - but says such change involves picking players he believes in even though it may be "a bit early for them".
Swansea striker Tammy Abraham, Liverpool defender Joe Gomez and Crystal Palace midfielder Ruben Loftus-Cheek received first call-ups for November's friendlies, while Manchester United's versatile winger Ashley Young was recalled for the first time since 2013.
"We had to qualify, so to fiddle too much with the team and change the team while you are still having to win, and you're not certain whether the lads are going to be able to go in and handle it, is difficult," Southgate added.
"Now we've got a phase where, OK, let's see what's possible here: how can we evolve the team, how can we take it forward, how can we give some of the young players that we've seen over the summer coming through?
"And whether I see the benefit of that, or whether other England managers down the line see the benefit of that, I think it's the right thing to do for English football."
Southgate left Liverpool duo Daniel Sturridge and Alex Oxlade-Chamberlain out of his squad and also omitted Manchester United defender Chris Smalling.
"Some of those guys are not playing regularly with their club at the moment," Southgate added.
"They need to be in a rhythm of playing if they are going to come in and be successful with us. There are positional things too, we are changing our system a bit."
Southgate's switch to three at the back
While England conceded only three goals during qualifying, Southgate feels the style of play does not yet match one he fully believes in.
The former Middlesbrough manager deployed three at the back in England's last World Cup qualifier, a 1-0 win in Lithuania which meant the Three Lions ended their group campaign with eight wins and two draws from 10 matches.
"We discussed in the summer as a coaching team it would be a good route for us to go," he added.
"It allows us to build with the ball and have stability behind. It also may allow us to get a different profile of midfield players into the squad as well. So it opens up possibilities.
"We've qualified playing a certain way but don't feel that has worked as we would have liked it to. So now it's important to focus on the detail of how we use the ball.
"World Cup qualification games can be tough. but we haven't really played in the style that I believe in. There are certain areas of our game that need to evolve."
Goalkeepers: Jack Butland (Stoke City), Joe Hart (West Ham - loan from Manchester City), Jordan Pickford (Everton)
Defenders: Ryan Bertrand (Southampton), Gary Cahill (Chelsea), Joe Gomez (Liverpool), Phil Jones (Manchester United), Harry Maguire (Leicester), Danny Rose (Tottenham), John Stones (Manchester City), Kieran Trippier (Tottenham), Kyle Walker (Manchester City)
Midfielders: Dele Alli (Tottenham), Fabian Delph (Manchester City), Eric Dier (Tottenham), Jordan Henderson (Liverpool), Jesse Lingard (Manchester United), Ruben Loftus-Cheek (Crystal Palace - loan from Chelsea), Raheem Sterling (Manchester City), Harry Winks (Tottenham), Ashley Young (Manchester United)
Forwards: Tammy Abraham (Swansea - loan from Chelsea), Harry Kane (Tottenham), Marcus Rashford (Manchester United), Jamie Vardy (Leicester)