"I spoke to Mr Mourinho and he said he quite likes the look of him so he wants to keep a close eye on him.
"I'd have taken Scott on loan again over Cristiano Ronaldo or Kaka any day.
"Teams are only as strong as their weakest link and what we try to do is strengthen in our weakest areas.
"When we lost Scott, we lost a great impact player but now he's not around we don't quite have that same threat."
Holloway has backed Sinclair to go on to become a huge star for Chelsea and England.
He added: "The world's at his feet but it's up to him now.
"If he keeps his feet firmly on the ground and things don't go to his head, then he's got all the attributes that a young man who's hoping to play for their country needs."