Ole Gunnar Solskjaer reportedly launched a 'brutal' verbal attack on Romelu Lukaku prior to the striker's deadline-day move to Inter Milan.
The Belgian, who joined Manchester United in 2017, completed a club-record £73m transfer to San Siro on Thursday after falling down the pecking order under Solskjaer.
Lukaku stirred tensions with the club after posting confidential results of a speed test exercise of first-team players at Carrington last week.
According to The Mirror, the 25-year-old was subject to a furious tirade from Solskjaer for posting tests results which undermined teammate Luke Shaw.
Lukaku was granted permission to leave Carrington on Monday - a day off for United's senior side - to train with Anderlecht's reserves, but will reportedly receive a heavy fine from the club for failing to return.
United did not land a replacement for Lukaku, with Solskjaer said to be happy with promoting youngster Mason Greenwood to a more senior role this season.