Man Utd's Gibson stays with Republic of Ireland
Fifa has ruled that the FAI may no longer quote the Good Friday Agreement as a reason for drafting up players born on the island of Ireland.
The FAI can now only use players born in the Republic, or whose parents or grandparents are born in the Republic.
The world governing body will not impose any sanction over Gibson's involvement for the Republic of Ireland in the Euro 2008 qualifiers.
The 19-year-old Gibson is currently on loan from Manchester United at Wolves but is suffering from a broken toe.