The Spaniard enjoyed a fantastic season last year but reports now suggest Herrera has fallen out with the Manchester United boss after an incident in April.
The midfielder is believed to have invited a friend with close links to Celta Vigo to United’s training ground shortly before United played the Spanish club in the Europa League semi-final, according to The daily Mail.
This saw him receive a dressing down from Mourinho behind the scenes.
Herrera has only started one game for the club this season and is yet to sign a new contract extension, with his current deal up at the end of the season.
Mourinho praised the midfielder last month but their relationship has taken a noticeable turn.
“We used to joke that he was Jose’s golden boy, and they were always chatting about the game,’ a source told the Mail.
“But the dynamic has changed since the end of last season. It’s not the same.”