The National Football League returns this weekend, with Tyrone's return ensuring the most competitive Division 1 for some time. We look at some of the sub-plots that may evolve.
Now that Jack's back. . .
Jack McCaffrey's return after a year out opens up the possibility of structural change for Dublin. With Cian O'Sullivan sure to be a pivotal figure again at centre-back, how do three fit into the two other positions across that line?
John Small, such a success as McCaffrey's direct replacement, will be hard to shift, while James McCarthy is untouchable. Is Niall Scully, star of the O'Byrne Cup campaign, out of the equation?
McCaffrey might have to sweat it out some more or he could make the move to midfield, a position he illustrated his suitability for when driving that second-half comeback against Cork in last year's League game.
Dubs' post St Patrick's Day league record vulnerable?
So many records have been established under Jim Gavin's stewardship of Dublin over the last four years but one of the most interesting is their loss of just one post St Patrick's Day game from 37 played - the 2014 All-Ireland semi-final ambush by Donegal.
Among that bulging catalogue of victories are all 12 they have played in the League. But that could come under threat in this campaign with a trip to Tralee to play Kerry on the day after St Patrick's Day.
Even allowing for Dublin's strength in depth and the nature of the pre-season activity, the Dubs' O'Byrne Cup win on Sunday is arguably most damning assessment yet of the chasing pack in Leinster.
Who is 'second best'? The smart answer is the Dublin reserves and that may not be far off the mark.
Westmeath have reached the last two provincial finals, courtesy of wins over Meath and Kildare, but they languish in Division 4. By virtue of superior League status Meath and now Kildare can claim shorter distance to Dublin's slipstream, so their meeting in Navan this Sunday takes on added significance.
Mayo goalkeeping revisionism?
How much does a mistake in an All-Ireland football final change Rob Hennelly's status in the eyes of the Mayo management?
If he was re-introduced, after sitting out most of the summer, for the All-Ireland final replay because of the leverage his kick-outs apparently give the team, as opposed to David Clarke, does that still apply now?
By restoring David Clarke as No 1 will it be a tacit admission that the decision to replace him between the finals was wrong in the first place?
Questions that the League may shed more light on.
Change of Kerry Keeper?
Brian Kelly and Brendan Kealy have alternated as No 1 goalkeeping choices over the last four years but now they face the threat of two good prospects displacing them, U-21 custodian Shane Ryan and Dr Crokes' Shane Murphy.
Murphy's kick-outs, as Crokes reclaimed their Kerry title last October, were laser-like.
When Lee Keegan went off on a black card in last year's All-Ireland final replay, Stephen Coen seamlessly stepped into his place, offering a decent security presence around Diarmuid Connolly, something Mayo couldn't really have countenanced in the build-up.
Keegan offers so much more in advanced positions but being detailed to mark the top opposing attackers has made it hard to express that.
It's something previous Mayo managements have grappled with but the punch he could potentially give their attack is worth examining again.
Time to cut Murphy some league slack
Michael Murphy is reportedly in the shape of his life, having completed his 'Toughest Trade' with French Top 14 rugby club Clermont Auvergne last week.
His League appearance record is quite something, missing just one from 31 games since early 2013 (through suspension against Mayo in 2015). No other player surpasses that record over the same period of time.
Whenever he plays he is the centre of opposition attention and attrition. Donegal can't afford to be without him too often, especially with the drain of experience in the off-season, but to get more they might have to risk seeing a little less of him.
Rossies' middle muddle
"We have to figure out way of operating in the midfield area," declared then joint Roscommon manager Kevin McStay during last year's FBD Connacht League. More than a year on and McStay, now sole manager, is still facing much the same problem.
Last year during the League, they used Niall Daly and David Keenan - more noted as half-backs - and Ian Kilbride in different partnerships (but Keenan and Kilbride are currently off the squad), whiile Cathal Compton and Daly were together for championship.
Cathal Shine struggled with fitness, Kevin Higgins with injury but both are back in the frame now. On Sunday last Tomas Corcoran and Tadhg O'Rourke started together. Many options but no obvious solutions yet.
Harte's league anomaly
Tyrone's six successive McKenna Cup wins illustrate Mickey Harte's desire to compete in every competition but just one Division 1 title in 14 seasons goes against that grain. Watch that space.
Aidan Walsh impact
Plenty of players are returning after long absences but Cork's Walsh may be the most significant.