England Under-21 manager Gareth Southgate omitted Luke Shaw from his squad but was left in the bizarre situation of not being able to explain why.
Despite Manchester United boss Louis van Gaal's reservations, it was widely expected that Shaw would go to the European Under-21 Championship next month.
But the 19-year-old's name was not among a 27-strong party announced by Southgate at a press conference at St George's Park on Wednesday.
Shaw missed Manchester United's draw against Arsenal last Sunday because of fears he was concussed by James McArthur's flying arm in the previous weekend's game at Crystal Palace.
Southgate, speaking during a press conference from the broadcast media, stated that Shaw "medically was not fit'' to play in the tournament.
When pressed on the matter during a briefing with the written press later, Southgate would not elaborate on the extent of the injury.
The 44-year-old revealed certain Premier League clubs had objected to fitness or injury issues being released into the public domain.
"I cannot answer that,'' Southgate said when asked why Shaw was not included.
"We had a couple of young players with injuries in the last camp and we started to go into detail of (their injuries) and clubs aren't very keen on that.
"Medically we don't own the players. They could go into fixtures the following week and someone could target that.
"We live in a world now with security of information... medical negligence... that is the world we live in. We have to be mindful that the data on things like that are owned by clubs or the individual player. I know historically we have always said 'he has a groin, he has a hamstring, he has a ...'. Maybe (those days are over).''
It is the Football Association's policy that the exact detail of a player's injury should not be detailed if it is sustained while on international duty.
But England manager Roy Hodgson routinely divulges such information and some clubs are happy to do so too.
Shaw has had hamstring, ankle and groin trouble during his first year at United, which prompted Van Gaal to make his objections at a press conference last Friday.
The United boss said: ''He needs that rest. He crossed his limits."
Southgate denied Van Gaal's words had influenced his call on Shaw and insisted that he had decided to leave him out a couple of days earlier.
The former England defender stressed that United had not demanded that Shaw should be pulled out of the tournament, which runs from June 17-30.
"Luke hasn't been told to withdraw from the squad,'' Southgate said.
"What Van Gaal said hasn't inflamed the situation from our point of view.
"I have dealt with Luke the whole season and I know the player and the medical team are in constant contact.''
Tottenham expressed reservations over Harry Kane's involvement as he has played 58 times this year.
Southgate rejected accusations of double-standards.
"No, Harry's fit -- Harry's not injured,'' he said when asked what the difference was between Shaw and Kane.
Kane started the season as third-choice striker for Spurs but, with one match of the campaign to go, he has scored 30 goals.
The Spurs youth academy product also scored 79 seconds into his full England debut against Lithuania in March.
"His world's changed enormously. He's the pin-up boy and it's a wonderful story and we hope this is the next part of it,'' Southgate said.
"I think he's got a really strong mentality, he's very focused in his practice he's very focused in his belief in himself.''
Kane will join up with the squad a week after his team-mates because he has to play for Tottenham in their end-of-season friendlies against Malaysia and Sydney FC.
England dropped two points and conceded two goals in their qualifying group before beating Croatia in a play-off last October.
''We're going there with genuine belief,'' Southgate said. "The players are determined to win it.
''They have a chance to create a little bit of history, which is a great position to be in.''
Saido Berahino, Danny Ings, John Stones, Calum Chambers, Jack Butland and Carl Jenkinson are the other full internationals to be included in the squad.
Raheem Sterling and Ross Barkley - among others - were eligible too, but Southgate has chosen to stick with the majority of the squad that performed so well in qualifying.