The experienced Serbian will end his eight-year stay in Manchester after agreeing with David Moyes that it would be best if the 32-year-old moved on.
And you can't help but feel that both parties have made a mistake - especially Moyes.
Vidic has been a rock at the heart of the defence - and the club itself - during his trophy-laden spell in Manchester.
And despite playing less frequently these days due to injury problems, the aggressive defender still has a huge part to play at Old Trafford.
With Moyes having struggled in his early days in charge of the Red Devils, he should be looking for all the title-winning experience he can get.
Four huge players, and more importantly, four huge figures at the club.
And the consequences of allowing such experienced figures to move on too soon can be seen at rivals Arsenal.
Within three years of Arsenal going an entire season unbeaten, Arsene Wenger had allowed numerous experienced players to leave the club - most of whom didn't wish to leave.
Along with Thierry Henry and Patrick Vieira, Wenger also cut short the Arsenal careers of experienced campaigners such as Martin Keown, Ray Parlour, Sol Campbell, Robert Pires, Sylvain Wiltord and Lauren - and the list goes on.
Much like Moyes is thinking now, Wenger judged many of the older players' legs to have gone.
He put his trust solely in youth, ignoring the importance of a mature backbone to the side.
And Moyes is set to do the exact same.
Losing Vidic is now a foregone conclusion. However, should Moyes also allow Ferdinand, Evra and Giggs to depart, his United troubles could become far worse.