Will Gareth Barry be fit in time to prove himself?

It will be a close-run thing. The Manchester City midfielder will stay in England when the rest of the party flies out to Austria and has pencilled in a fitness test for 24 May, when England play Mexico at Wembley. If that shows a good rate of recovery, expect Barry to be in the final 23, to be chosen on 1 June – if not, Fabio Capello will have to dispense with his services at that point.

Crucially, if Capello picks him in his 23-man squad, then it is later discovered he is unfit, he can be replaced from outside of the 30-man squad named yesterday, so long as the change happens up to 24 hours before the start of the tournament.

Who are the certainties – and does Capello already have the final squad selection in mind?

No. A core of players can travel to England's Austrian training camp with some degree of comfort – including the three goalkeepers and four of the five named strikers (see below). But the only other cast-iron certainties are Glen Johnson, Ashley Cole, John Terry, Steven Gerrard, Frank Lampard, James Milner and Theo Walcott, though Jamie Carragher is surprisingly close to that status, too.

Injuries have made the initial squad far more fluid than other "long lists" in recent memory and by limiting himself to three goalkeepers the manager has given himself the chance to have a long, hard look at the questionable fitness of his players. The uncertainties explain why Capello has selected so many midfielders (12) and defenders (10). Capello struggled with his numbers yesterday: he talked several times about a 22-man final squad rather than 23 but he was quite clear on one fact: that he did not know his final squad.

"I have some doubts about some players, but I have to decide at the end of this period. Because I'm concerned about the injuries. This is a really important point for me. This period the players are not finished. It's a 10-day trial for these players."

Will Ledley King's knee hold up to the strain of the finals?

His inability to train means that Capello still seems undecided on what the defender will do with his time out in Graz and his coaching staff will maintain contact with King's coach Nathan Gardiner at Spurs, to establish the best fitness regime for him. But Capello's assessment of the player yesterday certainly gave a strong impression that he will be selected for South Africa and his four games in the space of 15 days during Spurs' run in has given the manager optimism.

For what it's worth, King was the second highest ranked player in the 'Capello Index' for the last four games of the Premier League season. There are no less than six centre-halves in the squad, suggesting Capello is keeping an open mind both about King and Rio Ferdinand's fitness. If both come through the test, Michael Dawson would probably drop out of the 23. Leighton Baines also looks more likely that Stephen Warnock to be the second choice left-back. Capello has selected both because of lingering concern over Ashley Cole's fitness.

Who will win the competition for places on the England wings?

The midfield department is crammed with an extraordinary number of wide players, with four right wingers alone in Aaron Lennon, Walcott, Shaun Wright Phillips and Joe Cole; Adam Johnson is arguably a fifth, given that he, a very left-footed player, has operated so successfully from the right wing for Roberto Mancini at Manchester City. So two of that five probably have to drop out.

Wright-Phillips is not a player who always seems to have impressed the manager and he has a lot to do but perhaps the most absorbing contest in this most fluid of squads is that between Johnson and Joe Cole. Cole's form when given the opportunity to play during the run-in has been excellent, capped by his role in Chelsea's 8-0 win against Wigan Athletic – a point Capello served reminder of yesterday. "In the last two months, he's got better and better. Now he didn't play because Carlo [Ancelotti] chose other players, but always he played well when he had a chance, whether for 20 minutes. We need players like him."

Cole looks like the individual more capable of offering a game-saving or match-winning moment. Johnson has never played for Capello but he is the coming man who can play on either flank and drifting between the two as he does for City. Cole may just edge this one, against considerable odds, but it will be tight.

Who might be England's surprise pick of the final 23?

Tom Huddlestone is not a player Capello has ever seemed to have much faith in and the manager's zealous pursuit of alternative central midfielders in the past few weeks – Paul Scholes and Owen Hargreaves – illustrates that he does not consider him the best. But with the prospect of Barry overcoming his ankle ligament trouble looking a remote one, a decisive holding midfield position could be there for the taking.

Scott Parker looks third-best in the race for it and Huddlestone has grounds to believe that he can force out United's Michael Carrick. Carrick has not played a full game for Capello since the defeat in Ukraine last autumn, when he was disappointing, and has dropped down the pecking order at Old Trafford.

Has criticism over the Capello Index distracted the manager?

The Capello Index was not a well judged enterprise – and not just because it ranks Manchester City's Kolo Touré as the best player in the Premier League. Capello was disgruntled when the issue was twice raised yesterday, looking to the Football Association's communications director Adrian Bevington to provide the answers. He said the FA "had to remove any controversy about the World Cup" and have done so "for a few months" by delaying the launch of the index until after the tournament.

Was moving for Scholes a sign of desperation?

Far from it. Scholes has been the outstanding central midfield player in the Premier League over the past six weeks and despite Sir Alex Ferguson laughing off the idea of a place in the squad holding no appeal to him, he is ranked eighth in the Capello Index.

Scholes, who retired from international football after Euro 2004 having tired of being played out of position by Sven Goran Eriksson, decided not to come out of retirement for the 2006 World Cup. Of players to have made over 250 passes this season, Scholes is the second most accurate in the Premier league, behind only John Obi Mikel of Chelsea, 89 per cent of his 1562 passes found a team-mate.

Capello's 30-man squad – and why he made his choices

Goalkeepers

Robert Green (West Ham United)

Age: 30 Caps: 9 Goals: 0

Joe Hart (Manchester City)

Age: 23 Caps: 1 Goals: 0

David James (Portsmouth)

Age: 39 Caps: 49 Goals: 0

Fabio Capello has created an extra place in his initial 30 by only listing three goalkeepers, with Ben Foster's expected absence confirmed. If either of his three are injured he can call up a player from outside the original list up to 24 hours before the start of the tournament

Defenders

Glen Johnson (Liverpool)

Age: 25 Caps: 20 Goals: 0

Stephen Warnock (Aston Villa)

Age: 28 Caps: 1 Goals: 0

Rio Ferdinand (Manchester United)

Age: 31 Caps: 76 Goals: 3

John Terry (Chelsea)

Age: 29 Caps: 59 Goals: 6

Matthew Upson (West Ham United)

Age: 31 Caps: 19 Goals: 1

Ledley King (Tottenham Hotspur)

Age: 29 Caps: 19 Goals: 1

Jamie Carragher (Liverpool)

Age: 32 Caps: 34 Goals: 0

Michael Dawson (Tottenham H)

Age: 26 Caps: 0 Goals: 0

Ashley Cole (Chelsea)

Age: 29 Caps: 77 Goals: 0

Leighton Baines (Everton)

Age: 25 Caps: 1 Goals: 0

There seems to be uncertainty in Capello's mind as to which of Stephen Warnock or Leighton Baines is the best back-up for Ashley Cole, with Baines the more likely. The omission of Phil Jagielka makes Jamie Carragher the back-up right-back and centre-half. With six centre-halves in the 30, Michael Dawson and Matthew Upson could go, though everything depends on Rio Ferdinand and Ledley King being fit

Midfielders

Aaron Lennon (Tottenham Hotspur)

Age: 23 Caps: 15 Goals: 0

Theo Walcott (Arsenal)

Age: 21 Caps: 9 Goals: 3

Gareth Barry (Manchester City)

Age: 29 Caps: 36 Goals: 2

Frank Lampard (Chelsea)

Age: 31 Caps: 77 Goals: 20

Steven Gerrard (Liverpool)

Age: 29 Caps: 78 Goals: 16

James Milner (Aston Villa)

Age: 24 Caps: 7 Goals: 0

Michael Carrick (Manchester United)

Age: 28 Caps: 21 Goals: 0

Joe Cole (Chelsea)

Age: 28 Caps: 53 Goals: 10

Shaun Wright-Phillips (Man City)

Age: 28 Caps: 30 Goals: 6

Tom Huddlestone (Tottenham H)

Age: 23 Caps: 1 Goals: 0

Adam Johnson (Manchester City)

Age: 22 Caps: 0 Goals: 0

Scott Parker (West Ham United)

Age: 29 Caps: 3 Goals: 0

There is a preponderance of wide players, with three right wingers. It looks like a fight between Adam Johnson, Shaun Wright-Phillips and Aaron Lennon for one place – but two could go if Theo Walcott is taken as a midfielder. Tom Huddlestone and Scott Parker could both miss the cut if Gareth Barry proves himself fit

Strikers

Wayne Rooney (Manchester United)

Age: 24 Caps: 58 Goals: 25

Emile Heskey (Aston Villa)

Age: 32 Caps: 57 Goals: 7

Jermain Defoe (Tottenham Hotspur)

Age: 27 Caps: 39 Goals: 11

Peter Crouch (Tottenham Hotspur)

Age: 29 Caps: 37 Goals: 20

Darren Bent (Sunderland)

Age: 26 Caps: 5 Goals: 0

Darren Bent, selected ahead of Bobby Zamora who undergoes surgery on his Achilles tomorrow, is the only one of the five who has to prove his worth in Austria. Capello has indicated he might take four strikers, with Steven Gerrard or Theo Walcott as the notional fifth

What next for England?

Saturday FA Cup final

Monday Travel to Austria for training camp

24 May England v Mexico (Wembley)

26 May Return to Austria

30 May England v Japan (Graz)

1 June Final 23-man squad named

2 June Squad fly to South Africa

7 June Possible friendly (tba)

11 June World Cup begins

12 June First game v United States