All Blacks icon Keven Mealamu admits he has "mixed emotions", after being ruled out of Thursday's Fight for Life clash with former NZ Warriors star Wairangi Koopu.
A routine pre-bout medical check with his doctor found he has a heart condition.
The 43-year-old is expected to recover and receive the all clear to fight in the future, with big ambitions of chasing the New Zealand title.
"It's a lot of time to put into something, and not be able to go through and see the results," Mealamu told Newshub. "But I'm also grateful we've picked this up now so we can do something about it."
The routine check picked up an irregular heart beat, which turned out to be a condition called atrial fibrillation. Although he feels fine, he won't enter the ring on Thursday night.
"I'm sure there's a way through this and I'm hoping we can do that, so I can pursue this - it's something I'm really passionate about.
"I'm feeling really confident and really good," he continued. "But it's something that's underlying and has possible risk with it as well
"Health comes first and family comes first."
The bout between former All Blacks Carlos Spencer and former league star Paul Whatuira will take centrestage instead, but the fire still burns for Mealamu to get in the ring.
"I can't wait to, firstly, get myself right and then work my way back to a great condition again.
"I'm very determined. When I think about the work that goes into this, the opportunity to fight under the lights, you want to be able to go out there and showcase everything I've learnt."
There's a growing, lucrative market for former athletes stepping into the ring. Both Mealamu and Liam Messam are keen to fight for the New Zealand title, and it's not just belts potentially on the line.
Promoter Dean Lonergan says there's a big market for former athletes in boxing, with rugby league legend Paul Gallen a prime example.
"Boxing can be a very lucrative income for retired footballers," Lonergan said.
"I've dealt with Paul Gallen, who's a great bloke, and he's made boxing his second career. In the last three years, I'd suggest he's earned millions and millions of dollars.
"I promoted one of his fights last year against Justis Huni and his payday was well into seven figures for one fight."
Lonergan insists there's no reason why the former All Blacks can't follow the same path.
"Keven and Liam, if they got it right, can earn millions," Lonergan continued.
"They can trade off something a lot of boxers struggle with - name recognition."
We haven't heard the last of Messam or Mealamu in the boxing ring.
Join Newshub from 6pm Thursday for live updates of Fight for Life
