After six surgeries to save his right leg after suffering compartment syndrome against Sydney Roosters in round nine, the 23-year-old Brisbane centre is back on the park in the NRL.
Mariner was too young to play in the 2022 World Cup, where Samoa made the final only to be beaten by Australia.
He debuted in 2024 and is now determined to add to his five Tests and take on the world champions on their own turf at the October/November tournament to be held in Australia, New Zealand and Papua New Guinea.
Just competing in the World Cup doesn't cut it for Samoa now. Winning it is the aim.
"I think that's the whole point," Mariner said.
"You're not going to go into a World Cup thinking that you can't win.
"There is massive belief from our nation that we can go all the way.
"I've got my eyes set for the World Cup ... but you get chosen from the way you play for your club team, so I have just got to make sure that I'm doing my job."
The backline Toa Samoa are assembling has a superstar status. On paper it is as good as any seen in modern times on the international scene.
Melbourne whiz kid Sua Fa'alogo and Dolphins try-scoing sensation Hamiso Tabuai-Fidow will fight out the fullback spot. The other outside backs include Brian To'o, Stephen Crichton, Murray Taulagi, Izack Tago and Mariner. Halves Jarome Luai, Blaize Talagi and Chanel Harris-Tavita add to the dynamic.
"There's obviously a lot of talent in that Samoan team and it's pretty exciting the squad that we're going to have this year," Mariner said.
"Anyone that gets chosen, they will deserve it."
The sense of expectation ahead of the World Cup has been building in the Samoan community.
Last year thousands of fans gathered in Logan to welcome the team ahead of the Pacific Championships.
Tabuai-Fidow, who was injured at the time, went on stage to tell the crowd he was switching his allegiance from Australia to Samoa for the World Cup.
The cheer he received was off the charts.
The Queensland star has been watching Fa'alogo carve up the NRL and can't wait to join him in camp.
"Sua is a special player, just with the speed and agility he possesses," Tabuai-Fidow said.
"I'm excited to see what he is going to be like when he gets older."
"The way he's been playing, I'm excited to hopefully put that Samoa jersey on with him and run alongside him at the end of the year."
Mariner can't wait to do the same. He was born in Auckland but was never selected for junior New Zealand teams growing up. He always chose to line up with Toa Samoa rep sides at any opportunity.
Mariner's deep regard for cultural heritage was the driver for his decision to reject an offer from Kiwis team manager Stephen Kearney to be part of the New Zealand setup.
He was flattered, but Toa Samoa is home and where Mariner's heart is.
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