As a picture emerged yesterday, of Nemanja Vidic signing his contract with Inter, Manchester United fans around the world were forced to confront the reality of Vidic's decision to leave. Next season, the club captain, a player who has been at the heart of United's defense since 2006, will be plying his trade elsewhere.
So why has Vidic decided to leave?
In the official statement put out by United in February, Vidic said:
I want to challenge myself again and try to make the best of myself in the coming years.
Of course, official statements rarely tell the full story. Given that United are in disarray at the moment, it would also have been reasonably challenging for him to stay and fight for the club, making the best of himself in the coming years at Old Trafford.
Central defenders have to change their game as they get older. When Sir Alex Ferguson observed that Rio Ferdinand had lost an "electric yard" of pace, he urged the player to adapt.
That Jose Mourinho intimated in January that he was keen on a new contract for John Terry, saying he believed him to be the best centre-half in the country, is a fine example of how the right manager can help a defender change the emphasis of their game to get the best out of themselves in the latter part of their career.
This has clearly not happened for Nemanja Vidic under David Moyes.
Broadly speaking, there are three potential scenarios which could be behind Vidic's decision to seek his new challenge elsewhere.
The first is fairly simple. It is that he genuinely wants to try something new before his career ends. If this is the case, then it seems reasonable. After eight years at the club, and in Manchester, he and his family may just want something different in their lives.
I believe Man United is the biggest club in the world and I think there's no point to go anywhere.
At the same time, he made reference to prior rumours that he was considering leaving United, saying "I have to say the last four years I was in that position as well," going on to say "I'm still here and I'm enjoying playing for this club. Nothing has changed."
Clearly something has changed now.
The second potential scenario is that Moyes and United's executive team are unwilling to meet Vidic's contract demands to keep him at the club. If there is a substantial difference between the player's valuation of himself (and what the market says he can get elsewhere) and Moyes' estimation of Vidic's worth, then it is understandable that the player seeks his full value elsewhere.
If that is the case, it is a risky decision on Moyes' part. Vidic has a fairly substantial history of serious injury, and Moyes may believe it is too much of a risk to keep him near the top of United's wage structure, but this would seem at odds with his handling of Rooney's recent new contract.
Perhaps (and this is pure speculation) Moyes and Vidic have not hit it off, and Moyes does not believe he can get the best out of Vidic, but if that is the case, it is further grist to the mill for those who believe Moyes has done a poor job of managing the transition from Ferguson's leadership.
Keeping senior players onside should have been a key part of his agenda, because Vidic would surely have something significant to offer if used correctly. Given how Mourinho has handled Terry this season, it is not unreasonable to suggest he would have handled the Vidic situation very differently, and United may be better off for it.
The third scenario is that Vidic simply does not believe in the "David Moyes Project." Given the dramatic shift in his position from August 2013 to February 2014, it does not take a huge leap of imagination to consider this to be a possibility.
If it is that Vidic has lost faith in United's hierarchy, fans will be hoping he has made an error. The evidence so far, Vidic's departure included, would suggest that he has not.