Eric Dier (Tottenham)
It's tough to call Eric Dier the weak link because Tottenham are a side renowned for their teamwork and tactical discipline with Mauricio Pochettino creating an extremely pleasing and effective side. Dier has been marshalling the midfield for both Tottenham and his national side England for a while now too, something which should rightfully be commended.
However, when considering the other 10 players around him for his club, he starts to appear as the weakest member of the side. Starting out in defence, Dier has absolutely no chance splitting up arguably the best centre-back partnership in Europe in Toby Alderweireld and Jan Vertonghen.
In their usual front four of Harry Kane, Heung-Min Son, Cristian Eriksen, and Dele Alli, Spurs have attackers completely in sync with one another. They're clearly a side strong in every department but Eric Dier just doesn't offer as much as the others. He's a capable defensive midfielder, certainly, but he lacks the athleticism required to truly be elite in the position.
There's the suspicion also that Spurs' other options for his position - Victor Wanyama, Mousa Dembele, and Harry Winks - provide something more respectively and will eventually move Eric Dier out of the first team. Dier is akin to a player like Jordan Henderson: competent, dependable, but lacking the extra ability to play for a title-winning team.