Phil Jones has to "toughen up" if he is to stand any chance of fulfilling the lofty predictions made for his career in both an England and Manchester United shirt, according to Roy Keane.
Jones and Chris Smalling have been chosen from a struggling United side to provide defensive back-up in Roy Hodgson's World Cup squad but Keane believes neither has developed enough to give the England manager any great confidence should Phil Jagielka or Gary Cahill be sidelined in Brazil.
Both Jones and Smalling, Keane suggested yesterday, have "gone backwards" in recent months.
As well as the two young centre-halves, Keane also listed a number of others he believes failed at Old Trafford this season, naming Antonio Valencia, Ashley Young, Nani and Michael Carrick.
His dissatisfaction with the current United set-up extends off the field: Ed Woodward, the chief executive, needs to "take a look at himself" over the disastrous start to the post-Ferguson era.
"They have certainly not had great seasons," said Keane of Jones and Smalling.
"I don't think Roy Hodgson had great options in that position.
"Roy's obviously seen enough of them [for them to go to Brazil] but they won't be going into the World Cup in great form.
"Should they count themselves fortunate? They've probably just about done enough. If one of them had been left out I don't think it would have been a big shock. They better enjoy it while they are over there."
Asked whether the World Cup offered a potential platform for the two United players to prove themselves, Keane was withering in his response.
"They've had a platform for the last couple of years," said Keane.
"We were told two or three years ago Jones was going to be the new Duncan Edwards, Smalling was this big hope. I've watched United live nine, 10 times this year and they have been none of those things. If anything, I think they have gone backwards.
"They need to do a lot better if they want to cement their place at Manchester United and for United to win trophies.
"Jones needs to toughen up. Every time I see him he is getting carried off. He's got to toughen up – he's playing for Man United."
Jones, whose shoulder injury may yet keep him from Brazil, joined United from Blackburn in 2011 and made his England debut in his first season at United.
His form in that debut campaign prompted Sir Bobby Charlton to compare him to Edwards.
As recently as last season, Sir Alex Ferguson said of Jones "arguably, the way he is looking, he could be our best ever player".
This season though, Jones has struggled for consistency – he is far from alone in that regards at Old Trafford – and to establish himself in one position, as well as enduring further troubles with injury.
Keane believes United have to rebuild extensively if they are to compete again next season but the former United captain also insists it is an opportunity to start over under a new man – he backs Louis van Gaal – that should be welcomed by all at Old Trafford.
"They have to recruit in the summer," said Keane.
"It's the spine of the team. United have come up short defensively, and in the middle of the park they have not done enough.
"You watch any of the teams that are winning trophies – and I'm stating the obvious – you've got to have a strong spine, goalkeeper, defender, midfielder and striker, and United have been short in two of those areas. It makes it very difficult to win trophies.
"There are fine lines between winning and losing. This year Liverpool have improved five per cent and United have gone back five per cent.
"There have been so many changes at the back, players have come in that haven't come on.
"You've got Evra leaving, Vidic leaving – they need five or six players in: left-back, right-back, midfielder, winger. You shouldn't be afraid of rebuilding, you should be excited about it."
Keane thinks that United were too quick to discard David Moyes, suggesting the Scot was not given enough time to build his own side.
"He had one transfer window, and it's not always down to the manager when players don't come in," said Keane. "I think Ed Woodward needs to look at himself. He's got to get deals done."