There will have been a few nervous glances at England training this week.
As Roy Hodgson's squad prepare for friendlies against Chile and Germany, his players will have been checking out the competition.
Not the competition for a place in the team for the two games at Wembley but competition for a place on the plane to Brazil next summer.
But others will be anxiously doing the maths, working out how many defenders, midfielders and strikers Hodgson is likely to pick and who is standing in the way.
But it's an equation that includes an unknown quantity in Phil Jones.
Jones' England career started at right-back against Montenegro in October 2011. His second cap, a month later, came as a midfielder against Spain.
His last appearance, against Scotland in August, came as a centre-back, his first taste of senior international football as a central defender.
For Manchester United, he started the season as a right-back against Swansea. When David Moyes broke up the Rio Ferdinand-Nemanja Vidic partnership after the defeat at Manchester City, it was the 21-year-old who filled in.
Moyes has made use of Jones' flexibility this season and it will benefit Hodgson in the summer. But other England hopefuls are likely to pay the price.
Jones is a manager's dream when there's a major championship to plan for. He's comfortable at right-back and at centre-half, and his last three games for United have shown he's capable in midfield, as well.
Jones is likely to board the plane to Brazil primarily as back-up to first-choice centre-halves Phil Jagielka and Gary Cahill. But his effectiveness at right-back means Hodgson shouldn't need another alternative to Kyle Walker. That could mean Glen Johnson misses out.
And if Hodgson is confident enough in Jones's ability in midfield, it could cost someone else their place.
For the England manager, though, it opens up a number of possibilities. He can afford to take a fifth striker (he only took four to Euro 2012) or a wild-card pick such as Ravel Morrison or Ross Barkley.
But Hodgson's gain will mean others are forced to watch the World Cup from afar this summer and ensure Jones is the subject of more than one funny look at training this week.
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