Ill-tempered Portugal clash leaves O'Neill short
With an hour gone at Windsor Park on Friday night, O'Neill would have been contemplating a famous World Cup qualifying victory with his side 2-1 up and Portugal having lost Helder Postiga to a red card.
Brunt and Lafferty will now be absent when their team-mates fly to Luxembourg this morning and O'Neill has other problems too.
Both were substituted in the second half in some discomfort, while an IFA official said that Niall McGinn is also nursing an injury.
"We will have to sit down and assess our options," he said. "As well as the red cards the biggest blow is a couple of injuries. Wardy is possibly out and Fergie may not be available, so that will give us something to think about."
O'Neill has limited options outside of the squad and appears unlikely to delve into a very inexperienced under 21 pool.
"You have to look at the players that would be available," he said. "Stephen Robinson has the under 21 lads in Belgium now and it would be a bit unfair to call on his players. Most of his lads have no first-team football experience . . . it's a big ask."
Paddy McCourt is an obvious solution to bolster the numbers. The winger was not originally selected after a disrupted pre-season left him short of match fitness, but he is now in full training with new club Barnsley.
Reduced numbers meant O'Neill was already forced into brave team selection against Portugal.
He pitched 21-year-old MK Dons defender Lee Hodson against Ronaldo at right-back, while attacking midfielder Brunt was deployed as an emergency left-back. Both selections raised eyebrows, but O'Neill believes he had no real choice.
"They are only gambles if you have got other options," he said.
"It wasn't really a gamble, it was a no-brainer."