The news of Pep Guardiola going to Bayern Munich throws the Sir Alex Ferguson succession debate into the melting pot at Manchester United.
We may never know what transpired between the two when they met in New York recently, but at last week's United press conference Sir Alex looked genuinely surprised.
Surely there is a master plan in place, and it is not just left to Sir Alex's whim as to when he goes? You would expect David Gill, Sir Bobby Charlton and the Glazers to be in the loop.
So now we can conclude that either Guardiola was never in the plans; or that he didn't like the uncertainty and chose a world-class club who want him now; or that Sir Alex plans to step aside in three years.
Because unlike Chelsea, Bayern will give Guardiola all of his three years to make an impact, whatever happens. It doesn't necessarily upset United's plans, because Pep will be getting good experience with Northern European football.
The alternative is either that United had targeted Guardiola for next season and now have to go to a Plan B, or that they never had him lined up anyhow.
In which case we are probably looking at David Moyes, Ole Gunnar Solskjaer or Gary Neville, with Jurgen Klopp as the best outsider.
How does this affect Sir Alex's tactical thinking?
If, as has been suggested in the past, the timing of Sir Alex's retirement is totally in his own hands, then he must now realise he has at least three years, provided United can continue to succeed.
More to the point, three years would give him sufficient time to notch at least one more Premier League title, have three or maybe four more shots at the Champions League and to put Manchester City firmly in their place.
But what he must surely realise is that United aren't serious contenders for the Champions League at the moment, unless they get lucky like Liverpool and Chelsea.
It is not just that several teams have improved, with or without financial enhancement; it is also that United have regressed tactically and still haven't shown how they would get past Dortmund, let alone Barcelona, if they get that far.
There is evidence recently of some tactical experimentation to an extent not really seen since Carlos Queiroz was Assistant Manager. Indeed, if Ferguson is hankering after more trophies and especially the Champions League, he could do with a Queiroz, Didier Deschamps, Laurent Blanc or similar to solve the European conundrum.
He does have Rene Meulensteen, but the Dutchman is more of a technical skills coach.
The fact is that if United had the 11 best players in the world, they could probably play 4-4-2 or 4-4-1-1 all day long and crush the opposition.
They don't and, with the major titles in mind, Sir Alex is tinkering with his tactics as well as his lineups to try and find a winning formula for all circumstances.