Mourinho previously criticised Chelsea midfielder Loftus-Cheek's workrate.
Loftus-Cheek, who is currently on a season-long loan at Crystal Palace from Chelsea, hit the headlines after starring for England on his senior international debut against Germany last week.
However, the 21-year-old has endured a challenging time at club level as he has found his opportunities restricted at Chelsea, with his father believing that Mourinho is the main culprit with regards to Loftus-Cheek's lack of game time.
Trevor Loftus-Cheek told the Daily Mail: “Jose Mourinho held him back.
“He should have been playing. Everyone behind the scenes was asking: ‘Why isn’t he playing?’
“If Ruben was playing for Mauricio Pochettino, he’d have 70, 80, 90 first team appearances by now.
“He is like a Rolls Royce. He used to win all of the player of the year awards. But once Chelsea clapped eyes on him they knew what he was. They knew he was special.”
Mourinho gave Loftus-Cheek his senior debut when Chelsea took on Sporting Lisbon in the Champions League in 2014 but the prospect has so far been unable to make a sustained breakthrough into the first-team at Stamford Bridge.
At one stage Mourinho criticised Loftus-Cheek's workrate and the Portuguese, who is now in charge of Manchester United, was left frustrated by the youngster's approach to games, as reported by the Mirror.
Loftus-Cheek has only impressed in patches for Palace this season but his display for England against Germany, in which he demonstrated his excellent technique, provided a reminder of the undoubted quality that he possesses.