Applications to fill the void left by Dublin City are being submitted, and the FAI hope to have finalised the identity of that 22nd league club by the end of December.
FAI chief executive John Delaney says it would be preferable to have an even number of teams competing in the Premier and First Divisions next season.
However, he warned clubs interested in becoming the new "entity" that they must meet and fulfil the same club licensing criteria as other sides.
If and when this is achieved the FAI's Independent Assessment Group will then determine the suitability of each candidate.
"Were not going to pick somebody for the sake of it," Delaney warned. "It's preferable to have an even number of teams but if they don't meet the criteria, they don't meet the criteria."
Delaney refused to reveal how many clubs had applied to date but said the selected club would not receive a year's grace or leniency.
"It's not fair to say how many have applied because it only leads to speculation. . .but they'll start from year one," he said.
"The season starts in March and the new entity will be part of that."
Following the merger between the league and the FAI, the make-up of both divisions next season lies in the hands of the IAG, who are using on-and off-field criteria to determine which clubs contest the two divisions, and that group's decision will be announced on December 11th.