#3 Sergi Roberto (Barcelona)
Sergi Roberto can be called as Ernesto Valverde's key-man when it comes to attacking strategies. The dynamic Spaniard can play as a winger, midfielder or as a full-back, thus expanding the Barcelona's tactical options.
With Nelson Semedo not being a regular starter, Sergi Roberto is most likely to start for the Catalans at Stamford Bridge. Plus, his heroics at Camp Nou in Barcelona's iconic comeback against PSG last year can't be forgotten. This shows Roberto's excellence, especially in the Champions League.
Roberto would be a lot influential in aiding the deadly Barca attacking which includes the likes of Messi, Suarez, and Rakitic. Also, he'd be a great asset in the defence. His pace and positioning would be needed to stop their biggest threat- Hazard, down the right side of the pitch.