Colm Keys: 'Five football puzzles to solve in a summer of intrigue'
One way or another the 2019 All-Ireland football championship will be a momentous one, yielding the first five-in-a-row or thwarting it for a fifth time.
Dublin's favouritism is beyond dispute but like their biggest rivals they too have subtle questions to answer as they look for something different to stay well ahead of the chasing pack.
Please log in or register with Independent.ie for free access to this article.
All of the protagonists have key positional and personnel issues to address in the months ahead.
Where will Cormac Costello fit in for Dublin?
Dublin's least impactful league under Jim Gavin did have some bright notes, most notably Cormac Costello's scintillating Croke Park form.
Against Galway and Mayo he was man of the match while his goal against Tyrone had teed up another potentially big performance before injury abruptly ended his night.
It's hard to believe that over the last six championship campaigns, since Gavin introduced him to the squad as a 19-year-old, Costello has started just twice, against Donegal in the 2014 All-Ireland semi-final defeat and last year's final 'Super 8s' game against Roscommon.
But now comes the question as to who does he displace from the current forward line?
Or do Dublin pair Raheny club mates Brian Fenton and Brian Howard together permanently at midfield with James McCarthy dropping back to the half-back line?
How relevant can James O'Donoghue be to Kerry again?
Much focus on Kerry inevitably falls on how well they integrate their All-Ireland-winning minors of the last five years and what structure their defence might take with personnel in mind.
But 2019 is shaping like a defining year for James O'Donoghue's career.
It's five years since he illuminated the championship and finished as Footballer of the Year. Since the All-Ireland semi-final against Tyrone in 2015 however, Kerry have played 14 championship games and the Legion man has only started and finished two.
His involvement in the league has been even less concentrated. Over the last four seasons Kerry have played 30 league games and O'Donoghue has started just three and finished two of them.
Shoulder injuries that required surgery topped his troubles and contributed to a loss of form.
His latest league campaign was reduced to just three appearances off the bench but there have been encouraging reports about him in recent games, particularly a challenge against Meath over the weekend.
Maybe his body has just been through so much over the last few years. But his latest effort to refloat one of the decade's most promising careers carries more importance than ever.
Can Donegal afford to keep Michael Murphy at full-forward?
Michael Murphy delivered a timely reminder in the Allianz Division 2 league final against Meath of what a destructive force he can be at full-forward when he remains sited there.
The conventional thinking is that Murphy should stay there and be their end product at all times but with Jamie Brennan's progress, Patrick McBrearty's rehabilitation almost complete and Oisin Gallen's promise (though he will miss much of the championship now because of injury), the temptation will be to put Murphy in the engine room where he was so effective last season.
How Murphy is deployed in the coming months is more critical to Donegal than perhaps any other player is to any team elsewhere.
Rob Hennelly or David Clarke?
Injury to David Clarke has nudged Rob Hennelly back into pole position.
James Horan's faith in Hennelly was rewarded with a fine performance in the league final, on top of his thwarting of so many goal chances against Dublin.
Clarke started one more regulation league game than Hennelly who drew level in the league final before starting in New York on Sunday.
Clarke has scarcely put a foot wrong over the last three seasons but Hennelly gives slightly more range from kick-outs and frees from longer distances.
The selection crux that Horan had in his previous term and that Stephen Rochford, somewhat fatefully had, is sure to surface for Horan again later in the campaign.
Where do Tyrone get most out of Mattie Donnelly?
Is there a more versatile footballer around than Mattie Donnelly?
Last year he was a pivotal figure in Tyrone's charge through the qualifiers and Super 8s with his ball-carrying power from deep positions.
Halfway through this year's league Mickey Harte gave him a more advanced role as a target man in the full-forward line alongside Cathal McShane and it had a transforming effect on Tyrone.
For Tyrone, there is much the same question as Donegal have with Michael Murphy. Where do they get most out of him?
To get to that next level his partnership with McShane should be given more time to prosper.