There had been reports on the media and talk among journalists about it happening, but I had dismissed it as a side effect of Thierry Henry's return to Arsenal. When a fresh story breaks, the press love to look for signs that something similar will happen elsewhere, and the reports of Scholes's return had the air of hope rather than expectation.
So it was a shock when the confirmation came through little more than an hour before kick-off. I never thought Alex Ferguson would go down that road. It was even more of a surprise to see him get on the pitch for half an hour, even considering United's two-goal lead and one-man advantage at the time.
United scored their three goals in the first half as a result of their high tempo, first on the counter attack and then as a result of Vincent Kompany's red card. When Scholes came on he did what comes naturally, retaining possession and slowing the pace down. As we have seen in their recent defeats to Blackburn and Newcastle, when this current United side plays at a low tempo they struggle.
You could not imagine the biggest clubs in Europe's other major leagues bringing back old stars who are well past their best, so it is quite remarkable that both Arsenal and United would do so. I worry that such moves risk damaging the credibility of the Premier League as a brand.
Scholes's return until the end of the season is bound to polarise opinion. It is certainly great for the player, who has stayed at the club even after retiring and has admitted repeatedly that he misses not being involved with the first team.
But I do wonder if the move is an ideal one for United, or at least if they should have even let it come to this at all. It is a shame that they did not invest in a proper replacement in the summer. Now they have been reduced to using one of the club's all-time greatest players as a stop-gap measure.
United were unlucky to lose Tom Cleverley to injury after he had such a good start to the campaign. But given that Ferguson knew about Darren Fletcher's ongoing health problems, relying on a young midfielder who only made his debut for the club this season risked leaving his squad exposed, and so it has proved.
Some people have said Scholes was already on his way out last season before his announced his retirement, but he still started more than half of United's league games. He was an important player in a very ordinary United side that won the title. The only better way for him to sign off would have been by winning the Champions League final.
When he announced he was quitting, the amount of column inches gushing forth praise for him was incredible, and deservedly so. His status as a talent unique to his generation was assured.
Now, with more credible title challengers in the form of City and Tottenham this season than there were last term, Scholes is putting his legacy in jeopardy. On Sunday, for example, it was his poor pass that led to City's second goal.
I just hope that United do not have to call upon Scholes's services too often between now and the end of the season, and that when they do he is able to at least able to avoid diluting the great memories we all have of him in his glorious prime.
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Something that concerns me even more than United having to recall Scholes is the performance on Sunday of Rio Ferdinand.
Just as against Newcastle in the week, for my money Rio was the worst player on the pitch at the Etihad Stadium. The absence of Nemanja Vidic is being made all the more glaring.
It is not necessarily all his fault: he looks like a player carrying an injury. He is not performing at full tilt at the moment. It is clear that he is trying to play within his limitations in order to not make the situation worse.
He is trying to avoid putting in the hard work when he needs to, but that means he is often stretching desperately to get himself out of trouble.
I recognise it in Rio because something similar happened to me in my last couple of seasons as a pro. I was scared of pushing myself too far because I didn't want to sustain an injury that would spell the end of my career, and that showed through in my performances.
I can see where Rio is coming from. With the European Championships coming up in the summer he is doing whatever it takes to avoid picking up an injury which, given his age and record with his fitness, could easily rule him out of the tournament.
However, in doing so he is performing well below his best, and risked losing his place in Fabio Capello's team anyway. It's a terrible situation to be in, and the end of the season feels like a long ay away for him at the moment.