Sergio Busquets (Barcelona) - Defensive midfielder: £60 million

Sergio Busquets might not have been in the best of form last season, but he is still the most valuable defensive midfielder in world football at the moment. Ranked ahead of Chelsea star N'golo Kante, the Spaniard will be looking to once again rediscover top form and anchor Barcelona's challenge for the League title.
The 29-year-old often does the dirty work in the middle of the park without which Barcelona cannot play the beautiful football they are renowned for. A hard-working player, he excels at breaking down opposition plays due to his positional sense, defensive attributes, tactical intelligence, and ability to read the game.
The importance of Busquets to the team can perhaps be best summed up by Real Madrid defender Sergio Ramos.
In spite of the rivalry and one incidence of a red card earned due to Busquets' play acting, this is what Sergio Ramos had to say about him: "There are a number of players I like, but the one we perhaps need is Busquets,"
Valverde will be hoping that Busquets lives up to his potential this season.
This video gives a brief glimpse of what Busquets brings to the team.