Former WBO light-heavyweight champion Nathan Cleverly says he could retire if he loses his rematch against Tony Bellew.
Cleverly beat Bellew in 2011 to retain his WBO light-heavyweight title, but both have moved up to cruiserweight since then.
The rematch will be in Liverpool on 22 November with Bellew suggesting defeat could force the loser to quit.
"The loser? Who knows, maybe it's time to walk away," Cleverly said.
"The winner goes on to fight for the world title. It's a massive opportunity.
"There's so much on the line in this fight and I can't afford anything else.
"It's a must win and I will give it everything. I will give it absolutely everything to take this guy down."
The 27-year-old considered retirement after losing his WBO light-heavyweight title to Sergey Kovalev in August 2013, his first professional defeat.
Bellew moved up to cruiserweight after losing to Canada's Adonis Stevenson in Quebec City in November 2013, but has also claimed two victories since then.
The Liverpudlian says he intends to end Cleverly's career when they meet once again at the Echo Arena on 22 November.
"I have been waiting for this fight for three years and now it is here revenge is the only thing on my mind," Bellew said.
"This is a chapter in my life that I need to close and I will do that by ending Nathan Cleverly's career.
"I am in the sport to be successful and win titles, but this fight means more to me than any of that - this is personal, and he will not want to enter a boxing ring after I have finished with him."