"It was really hard for me because I didn't want to stop. It's always been a dream for me ever since I was young to play for the Warriors and hearing that from the doctors was a bit disappointing and discouraging.
"I was always short of breath," he said. "I still get troubled by it but I have breathing exercises that I have to do every night before I sleep just to clear my lungs."
The talented ball-player always had big ambitions but, perhaps due to his condition, was unable to impress junior representative selectors until he was 18.
He eventually won a start with the Warriors NYC side in 2012 and impressive showings during the 2013 season saw him promoted to the Vulcans before he was upgraded to a fulltime NRL contract.
He remained a stand-out performer in the NSW Cup and made his NRL debut off the bench in the Warriors' Anzac Day clash against the Gold Coast, before finally winning a starting berth for today's game, as a fill-in for NSW State of Origin back-rower Ryan Hoffman.
"I'm more of a runner or strike player but I'm just working on things the coach wants me to do so I can stay in the team," he said. "He [coach Andrew McFadden] gave me goals to work on while I was playing NSW Cup, to be strong on defence.
"I always look for the big play on attack, so he was telling me not to think about the offloads and just run hard and tackle hard. That was his main message. To 'be a wall' were his exact words."
His inclusion means disruption for the starting left-edge for the first time this season, but five-eighth Chad Townsend is confident Faitala-Mariner can slot in comfortably.
"We've been pretty lucky as a left-edge to have the same group for the whole first half of the season which has definitely helped us grow our combinations," said Townsend.
"We've seen that with a couple of tries we've scored down that way, so we've been blessed about that and with Ray coming in we're looking for him to do a job this weekend.
"He's obviously a big fella and runs some pretty good lines so I'll be looking to utilise his best qualities."
The young rookie has other talents off the field too, and from all reports is a highly skilled piano player, and musical ability runs in the family.
"Sole Mio [New Zealand musical trio] those are my cousins so I guess you could say I'm from a musical background.
"I play a little bit of piano but it's mainly church songs, none of this R'n'B stuff.
"We have a piano at home so whenever I have an argument with my siblings I'll just go to the garage and play.
"It takes my mind off things," he said.
NRL, round 14
• Warriors v Roosters
• Tonight, 8pm
• Mt Smart Stadium
