Croke Park officials are on the trail of counties who allegedly broke the rule banning squads from undertaking extended training camps in the run-up to the championships.
Armagh, Wexford, Dublin, Donegal and Mayo are among those believed to be under investigation.
The penalty for breaching the rule is loss of home venue for one Allianz League game in the following season.
Several reports of squads either travelling overseas - as in the case of Armagh, Wexford and Dublin - or holding camps locally have appeared in recent weeks, prompting an intervention at official level.
It's understood Croke Park authorities have written to the counties, seeking clarification before deciding how to proceed.
Wexford hurlers and Dublin footballers have spoken openly about their trips to Portugal and France, insisting that they did not involve training.
Lee Chin maintained that it was a case of the Wexford players deciding to "go off together and have a bit of fun in each other's company", while Dublin's Michael Darragh Macauley spoke of "paying respects to the Irish who fought in World War One".
Croke Park remains sceptical of claims squads would interrupt their Championship preparations to embark on continental jaunts that did not involve training and are seeking explanations.
"We have a duty to investigate all reports of counties who allegedly broke the rule. Counties backed it in the interest of the club game and it has to be upheld," said a GAA source.