Mata Chelsea’s player of the year last term was left out of the squad altogether for Saturday’s 2-0 Premier League victory over Fulham prompting renewed speculation he could leave the club.

Napoli have been linked with a move for the Spaniard in January and it has been reported that 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 said. ‘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.

‘A manager needs to take a decision and in this case it’s a tough decision. Jose will know how to manage them well.’

Asked if Mata had a future at Chelsea Grant added: ‘I think yes. He’s a great player he’s won games gave assists and scored goals.’

Grant succeeded Mourinho when the Portuguese was sacked in 2007 but his own reign lasted just one season and he was axed after losing the Champions League final to Manchester United.