Italy defender Leonardo Bonucci is taking legal action against his former club Juventus after claiming he was left feeling "humiliated".
Bonucci joined Union Berlin for free in August after being frozen out of the Juve squad following a reported fallout with manager Massimiliano Allegri.
"I have decided, after great suffering, to pursue a lawsuit against Juventus," said Bonucci, 36.
"I felt drained of everything, humiliated."
Bonucci spent 12 years in Turin over two spells and won Serie A eight times with Juventus in addition to helping Italy win Euro 2020.
He was left out of Allegri's squad for the United States pre-season tour and home friendlies prior to the start of the 2023-24 Serie A season.
"My rights stipulated that I should have trained with the team regardless of the technical choice and been put in a position to physically be able to play during the following season," Bonucci added in an interview with Sport Mediaset published on Thursday.
"This was not granted to me, I no longer trained with the team. I couldn't do what I love most.
"I am pursuing this cause because the people who were supposed to let me end my career with Juventus in a respectful and worthy way have not done so."