Midfield
Defensive midfielder - N'Golo Kante
This one is a no-brainer. Joining Chelsea in 2016 after winning the league with Leicester City, N'Golo Kante was Chelsea's best player in his first season as he led them to the Premier League crown under Antonio Conte. For that season, he was named the PFA Player of the Year.
Currently, Chelsea's best player, Kante has been the most consistent defensive midfielder in the world for the past few seasons and his presence in the middle of the park is invaluable. Although not a physically intimidating guy, Kante's persistence, positioning, stamina, and vision, have made him one of the best players in the Premier League.
An easy addition to this list, the £32 million which the Blues paid for him three years ago seems nothing in comparison to his value now.
Centre-midfielder - Cesc Fabregas
Signed by Chelsea from Barcelona in 2014, the former Arsenal captain experienced some of the best days of his career at Stamford Bridge. In a deeper creative role which utilised his amazing vision, he excelled in Chelsea's new style of play under Jose Mourinho, where he proved to be an effective assist-provider.
Fabregas had an amazing eye for a pass, as well as great technique on the ball which made him a brilliant midfielder during his time with the Blues.
He became the fastest player to reach 100 Premier League assists, and he played a vital role in both of Chelsea's league title victories.
Fabregas left the club in January having spent five amazing years at Stamford Bridge and established himself as an all-time Premier League great.
Attacking-midfielder - Juan Mata
Chelsea fans were heartbroken when they found out that Juan Mata was being sold by the club. Although he played for the Blues for only three seasons, it would be unfair to leave the Spaniard from this list.
During his time at Stamford Bridge, Mata won the Champions League, Europa League, and the FA Cup with Chelsea.
He was named Chelsea Player of the Year for 2011-12 and 2012-13 and was named into the PFA Team of the Year for the 2012-13 season. With 33 goals and 58 assists in 135 appearances, Mata was Chelsea's best player for the three years he was there.
It was only due to differences with Jose Mourinho that he was sold - who knew how his Chelsea career would have been otherwise?