Msts Hummels and Borussia Dortmund manager Edin Terzic were reportedly involved in a 'violent confrontation' ahead of the Champions League final earlier this month.
Dortmund overcame the odds to reach the biggest game in club football but came up short against Real Madrid at Wembley.
Days before the match, Hummels somewhat shockingly came out to heavily criticise his manager's tactics during their disappointing Bundesliga campaign.
Dortmund finished fifth and veteran centre-back Hummels was not a fan of how the team approached their games against those above them.
He told Bild: 'I was furious because I was of the opinion that Borussia Dortmund shouldn't play like that - against any opponent in the world.
Msts Hummels (C) and Edin Terzic (L) were reportedly involved in a 'violent confrontation'
'I didn't think it could go on like this. I felt insulted in my honour to stand on the pitch in that kit. So submissive, so inferior in footballing terms. The two Stuttgart games and the away game in Leverkusen. That was barricading with 11 men in the box.'
And Bild now claim these comments caused serious problems behind the scenes.
Their report states that the men were involved in a confrontation that became violent and 'so heated that the club discussed personal consequences'.
The pair were 'forced to make peace' to focus on the Champions League final but Sky Sports say Hummels is now only willing to stay at the Signal Iduna Park if Terzic goes.
Bild add that it is 'guaranteed' that one of them will be saying goodbye to the club this summer.
Hummels (L) publicly critcised his manager's (R) tactics before the final at Wembley
Hummels is in the midst over his second spell Dortmund with this last season his 14th for the club.
He will be taking no part in Euro 2024 having been left out of the Germany squad.
'I can understand the idea that a group has been growing since March,' Hummels told Bild. 'It's bitter for me as an individual because I'm currently one of the five best defenders in Germany,' he said. 'I have the self-confidence to say that.'
Defender Hummels is said to only be willing to stay at the club if Terzic leaves this summer
Asked about the reasons behind his omission, Hummels said: 'If I understood him [Nagelsmann] correctly,
'It was more about age-related issues like fitness. If I'd had a phase like the one I had recently before [the friendly fixtures in] March, maybe I would have been called up [and] for the European Championship squad as well.'