What it could mean for Gaelic football
Well, we can really say in the GAA 'We have seen it all now' with the news that Jim McGuinness is off to work for Celtic.
The role he will be playing is not the most significant thing, rather the fact an All-Ireland winning football manager will be on the staff of a leading European soccer club -- we can say that after Wednesday night, can't we?
GAA people in general will congratulate Jim and few will have any doubt he will be a great success.
He is young, qualified and talented, has the important sports psychology qualifications that very few managers in any of the football disciplines actually have and his dedication to a cause is surely not in doubt. So, let him off to make his fortune!
This major development is not, of course, a totally new departure and, just last year, Dublin captain Bryan Cullen was appointed to work with the Leinster rugby team, while fellow Dub Philly McMahon is joining the back-room team of Shamrock Rovers.
But McGuinness is the one who will arouse the greatest interest. Dozens of GAA players have over the years transferred to other sports like soccer, rugby and Australian Rules at the very highest level, so there must be something in the Gaelic football DNA that appeals to other football players.
The Donegalman will be very much at home in Glasgow, often referred to as Donegal's 'other county', but emotion or history will cut no ice with him.
There is no doubt he will be aiming for a top managerial job with Celtic or some other club in the years ahead, once he has mastered the differences between Gaelic and soccer on the administrative side.
His future with Donegal will most interest GAA people and, initially at least, he should be able to cope.
But whether he will be able to enforce the draconian discipline which he applied to Donegal players, who now won't see him quite as regularly, is another matter.
There is unlikely to be a rush of similar managerial transfers from GAA to soccer, however, although there are some like Kieran McGeeney, Justin McNulty, Niall Moyna or Jason Ryan who would be obvious candidates to transfer based on their qualifications.
And when Jim McGuinness moves into an actual soccer managerial role, we will wait with bated breath to see if introduces revolutionary tactics to the beautiful game like he did with Donegal in 2011/2012.