If David Moyes was in charge, maybe United fans could look forward to seeing Phil Jagielka in the squad, but it is unlikely that Louis van Gaal would be keen.
Will the new manager want an experienced head who can help bring through the young central defenders United already have?
Phil Jones said of Vidic in United Review last week:
You learn off him every day in training, even if he doesn't say anything, you just watch and learn. He's been a huge influence on my career at United and has really helped me along the way. I owe him a lot and I am grateful for everything he's done.
Or will the new manager want to bring in a younger defender, who still is relatively experienced but with years ahead of them to continue improving?
Here are eight central defenders United could see in their back four next season.