Northern Ireland manager Michael O'Neill says he would never consider Fifa eligibility rules when selecting his squad.

Northern Ireland's Nations League campaign starts away to Georgia on 25 September. Ceadach O'Neill is one of four teenagers in the squad alongside Blackburn Rovers defender Tom Atcheson, Everton forward Braiden Graham and Kieran Morrison, the Liverpool winger on loan at Sheffield Wednesday. Atcheson and Morrison were born in England but qualify through grandparents.

"Kieran deserved the chance because he'd been around the Liverpool first team," said O'Neill after naming a 28-man squad. "Braiden is the same. They merit a place over some players that aren't in my opinion. My job is to protect the national team and build the squad as strong as possible."

O'Neill cited Conor Bradley, Isaac Price and the Charles brothers as examples. He won his first cap at 18 in 1988 and noted Norman Whiteside's 1982 World Cup debut at 17.

"This is not new for Northern Ireland. We're doing it based on the level of the player," he added.