Former Manchester United physio Matt Radcliffe has accused Jose Mourinho of being a bully because of his treatment of defender Luke Shaw.
Radcliffe who worked with Shaw in his formative days at Southampton and still in regular contact with the 21-year-old thereafter believes Mourinho is not handling the situation well.
Shaw's application and work rate on the training ground was questioned by Mourinho last week.
He returned to the first team on Tuesday after holding talks with Mourinho earlier in the week, making a substitute appearance in the 1-1 draw against Everton, but despite making a positive contribution, the United boss said afterwards that he had to tell his player what to do on the pitch.
"I'm not sure what Mourinho is trying to do by coming out in the media and constantly having a pop at Luke," Radcliffe told ESPN FC.
"Some people would see it as bullying of a young player, but Luke will not see it like that. I know him and comments like this will just make him even more determined to get back into the United team.
"He has not come out in the media and made any comments about the manager in the media and he will not go down that road because he is not that type of lad. Luke Shaw just wants to play football and we all know that he will make his mark at United if he gets his chance."
Radcliffe added: "Luke is a machine. There are drills I have done on training pitches and he is the only one who can do it.
The kid has a wonderful physique and anyone who suggests his fitness is an issue at United right now are getting this completely wrong.
"I saw Luke a couple of weeks back and he was as fit as he has ever been and also in good spirits. He is just hoping he gets a chance to show what he can do in the United team and hopefully the manager gives him a break at some point.
"Luke suffered a very serious double leg break last season and he still gets twinges in that leg at times, but he has made a complete recovery from the injury now and just wants to get on with his career."
Radcliffe believes Mourinho's poor track record of enhancing the career of younger players in his two spells at Chelsea and now with United may explain why Shaw is struggling to make his mark at Old Trafford.
He also says Shaw would not be short of Premier League suitors if he decides to move on this summer.
"Mourinho has a history of sticking with older players and has shown in the past that he doesn't have much interest in working with kids," Radcliffe said.
"You look at the teams he had at Chelsea and now with United, he is not doing much for players like Marcus Rashford or Anthony Martial and Luke has fallen into that list as well.
"Hopefully Luke will get a chance to play a few games until the end of the season because we all know his ability when he is given the confidence to perform.
"I know that Mauricio Pochettino at Tottenham still has a lot of time for Luke after their time together at Southampton and he has a great record of promoting young English players. If it doesn't work out at United, there will be plenty of places Luke could go and Spurs would be at the top of that list.
"Maybe Mourinho could learn a few things from Poch and then he might get the best out of a player who has the talent to be the best full-back in English football for the next decade."