#3 Luke Shaw
Under Mauricio Pochettino at Southampton, Shaw became one of the best young left-backs in the world. United was quick to snap him up for the then world record fee for a teenager. He's had immense potential but his lack of fitness has always been an issue.
Shaw is fleet-footed and can dribble past defence well too, with a good ability to hold on to the ball.
After starting to have a breakthrough 2015/16 season under Louis van Gaal, he suffered that horrific double leg injury that kept him out for the season.
Needless to say, he hasn't been the same Shaw that came back and has shown very few glimpses of promise during his time at United.
He had 11 appearances in the league last season, and averaged 1.6 tackles and 1.7 interceptions, providing 1 assist in those games. He has performed better at the European stage, with 2.3 tackles and 1.3 interceptions per game.
With Young getting old and Darmian expected to leave, he can work his way through the first team and make a comeback into the team.
He's been working on his fitness proactively and was the first to report to the Carrington ground for the preseason.
If he manages to do this, there's no doubt that he'll have his standout season and hopefully make it back to the national squad.
Statistics - WhoScored.com