The Croatian veteran left Juventus for Al Duhail of Qatar, but not before fielding an approach from United.
Branchini told TMW Radio: "There are things of football that cannot be understood and therefore explained. Mario has a strong character, he is severe with himself and with others. In the summer there were facts that led to a moving away from the club, which nevertheless behaved well. In fact it was he who excluded himself when Juve told him that he would not enter the Champions League list.
"From there, there was a break with the coach, but the managers and the president they went out of their way to meet Mario, who was hurt at the time. Having said that, what moves the market is incomprehensible.
"He rejected United because the English club showed up 12 hours before the end of the market. And it was an unfortunate story, it would be unfair to give Juve responsibility, he suffered from it and eventually made this (Qatar) decision."