Gary Neville has criticised Manchester United defenders Jonny Evans, Chris Smalling and Phil Jones by saying he is waiting for "the penny to drop" for them and believes they still have to prove they can realise their potential.
Former United captain Neville, who works with Smalling and Jones in his capacity as an England coach, said he expected them to have developed more by now.
Last season the trio were the junior centre-backs at Old Trafford but with Nemanja Vidic and Rio Ferdinand having both left in the summer, and Louis van Gaal opting not to strengthen in defence, they are now senior to Tyler Blackett and Paddy McNair.
Evans is now 27 and has played 191 games for United, while Smalling, a 2010 signing from Fulham, is 25 and has 135 appearances for the club under his belt.
Jones, 22, is the youngest and least experienced of the trio but has played 115 times since his 2011 arrival from Blackburn and Neville said he thought the last two managerial appointments at Old Trafford would have benefited them more.
He told Stretty News: "When you are with England and you work with the likes of Smalling or Jones, you hope that a manager comes in and grabs them, plays them, trusts and puts belief in them.
"So when David Moyes came in last season we thought that would be good news because David likes British players. This season Louis van Gaal has come in. A great coach and someone that worked all over Europe.
"[You think] he'll get them good on the ball, good defensively, in good positions to receive the ball, opening their body out and passing forward with composure.
"For Luke Shaw it's perfect. The manager believes in attacking full-backs and Luke is fantastic going forward. Luke is powerful, quick and hugely talented. Then you want to get a grip on him and mould him into a world-class player.
"Then with the likes of Smalling, Jones and Evans we still have great hopes for that penny to drop."
Neville told them to follow the example of Darren Fletcher, who kicked on in 2008-09 to go from a squad player to a pivotal figure, and Cristiano Ronaldo, who took his game to a new level after the 2006 World Cup.
He added: "If you remember for many years we had players that potentially had it. Darren Fletcher all of a sudden became the most important person in the team for a few seasons. It was like: 'Wow, here we go, he's a player now.'
"Cristiano took two or three seasons and the penny dropped. People have got to remember the frustrating Cristiano to appreciate the great one.
"Aaron Ramsey at Arsenal is another example. You lose a bit of patience at times but you know they have the talent inside them and you think they've got the brain and willingness to do it.
"They're still developing and picking up injuries but when they stop and the penny drops you think: 'We've lived with his faults, development and now we're getting the benefit of it.'
"There is no doubt that Jones, Smalling and Shaw have talent but they need experience, maturity and injuries to stay clear and they will fly."