Antrim have become the latest Ulster county to vote against opening up Croke Park to rugby and soccer.
The Croke Park vote will dominate this weekend's GAA Congress
Five counties north of the border have already voted against deleting Rule 42 and Armagh are expected to follow suit in advance of Saturday's vote.
The Antrim vote was 52-34, closer than had been expected.
Despite the Ulster opposition, the latest forecasts suggest that the historic change could be accepted by the GAA's Annual Congress in Dublin.
The overall amount of votes at Congress will be 335 which will leave 224 as the figure needed to endorse change given the two-thirds requirement.
Former Antrim county board treasurer and ex-football boss Eamon Grieve was among those disappointed by the decision of his county.
"We could market Ireland far better if we could allow appropriate games to be played there," Grieve told the BBC.
"But some people would think that you would be less Irish, less GAA by moving in this direction."
Those favouring change have been boosted by unexpected backing from Tipperary and Waterford.
GAA president Sean Kelly is in favour of an historic change
And if Limerick, as expected, support change on Tuesday evening that would leave Cork as the only Munster county favouring the status quo.
All 12 Leinster counties seem set to also agree to the proposal to open Croke Park on a temporary basis during the redevelopment of Lansdowne Road.
That will mean that the overseas votes could ultimately decider the issue.
With many overseas units using facilities owned by other sporting organisations, that gives the proponents of change optimism that the historic change could indeed happen at Congress.
However, those in favour of deleting Rule 42 are worried that a secret ballot as opposed to an open vote in Dublin could spell the death knell for the motion.
A secret ballot could mean that a number of individual delegates might be tempted to not follow the mandated positions of their counties, which could have significant implications in a tight vote.
Seven counties have submitted motions on the Rule 42 issue although it seems certain that only one proposal will be debated at Congress.
GAA president Sean Kelly is among those in favour of the association opening Croke Park to other sports.