#4 Toby Alderweireld - £25.4 million
At 29 years old, Alderweireld is not getting any younger - which might be a reason Tottenham aren't worried he'd get signed to another club.
However, with a low release clause of £25.4 million, the club shouldn't be too confident that no other club would take interest in him.
The centre-back is very solid as well as being reliable and has not made a defensive error this season.
He is great on the ball and passes the ball very well but his best quality is arguably his leadership. He is constantly marshaling the backline and motivates his teammates when needed.
Whenever he has been out through injury, Spurs have struggled defensively.
With a defender like Virgil Van Dijk going for £75m, don't be surprised if Alderweireld gets the attention of clubs that could use some polishing in defence, such as Arsenal, or Manchester United.