#1 The underutilization of N'Golo Kante
Following his tireless displays from the base of midfield in Leicester's unlikely triumph in the 2016 Premier League season, N'golo Kante earned himself a well-deserved move to Chelsea the following summer.
He continued his all round hardworking performance at Chelsea and was deservedly named PFA Player of the Year as Chelsea romped to the title in Antonio Conte's first season in charge, which was an amazing feat, considering that players in Kante's position rarely get the accolades, but the diminutive 27-year-old's contributions were so obvious that he was a shoo-in for the award.
He has since established himself as arguably the premier defensive midfielder in the world, not afraid to do the dirty work and break up opposition play while his more creative teammates wreck havoc going forward.
Sarri's arrival has however seen Kante deployed in an unfamiliar role further up the field, as Jorginho occupies his preferred role at the base of midfield where he acts as a deep-lying playmaker.
While this has seen an improvement in his attacking contributions (he has scored 3 goals and assisted 2 as opposed to the one goal and assist he registered in each of the previous two seasons), there has been a concordant decline in his defensive output.
So far this season, the World Cup winner has managed 30 interceptions from 22 Premier League matches, which comes at a rate which will see him end the season considerably less than the 85, 82 and league high 156 he managed in each of the last three seasons.
His tackling rate has also nosedived, as he has managed just 36 so far this season, which comes at a lower ratio than the 113, 127 and league high 175 he made in the last three seasons respectively.
Kante's best work is best utilized as a midfield enforcer who is tasked with breaking up opposition play and while Jorginho has discharged his duties fairly efficiently, Sarri's trust in the Italian means that Kante would continue to be used out of position and this is a matter of consternation to a multitude of Chelsea fans.