Former Chelsea boss Avram Grant is surprised by the freezing out of Juan Mata.
It has been reported that manager Jose Mourinho's sparing use of the playmaker has caused friction with owner Roman Abramovich.
"I personally don't understand (why he left Mata out)," Grant told BBC Radio Five Live's Sportsweek programme.
"But in this position Chelsea have so many players, so if Oscar, Eden Hazard, or Willian are out people will ask why they are out of the squad or team.
"Mata was one of the best players in the midfield in the last year.
"A manager needs to take a decision and in this case it's a tough decision. Jose will know how to manage them well."