Mourinho is anxious not to place expectations on the Brazilian.
"Kaka hasn't played for six months, but it has actually been longer because he hasn't been in optimum form for a year and a half," said Mourinho.
"He is going through a natural process and we must continue to support him. He is a fantastic guy and a great player.
"He relies on his talent and speed, which doesn't make this situation easy for him. I didn't expect him to be the Ballon d'Or winner he was as soon as he recovered.
"We must be patient and allow him to work with no pressure. I don't put any pressure on him."