Juan Manuel Marquez and Mike Alvarado will clash in a welterweight eliminator in Los Angeles on May 17.
The fight, which will take place at a 143lb catchweight, will see the winner take on either Timothy Bradley or Manny Pacquiao, who fight at the MGM Grand in Las Vegas on April 12.
It means Marquez and Pacquiao may yet clash for a fifth time, while Bradley could end up in a rematch with Marquez, whom he beat on points in his last fight.
Alvarado is also coming off a loss, to Ruslan Provodnikov, the man who took the unbeaten Bradley to the brink around 12 months ago.
Pacquiao lost to both Bradley and Marquez in 2012 but his narrow points defeat to the former was controversial and their rematch next month is highly anticipated.