The World Boxing Organization (WBA) has obliged Golovkin (42-1-1, 37 KOs) to face Erislandy Lara (29-3-3, 17 KOs), who holds the regular WBA champion belt, QazMonitor reports citing Vesti.kz.
And Golovkin must do it within 120 days of his September clash with Canelo Alvarez if he intends to stay in the middleweight category.
According to ESPN insider Mike Coppinger, Golovkin will have five days to decide which WBA title he will keep if he defeats Alvarez on September 17.
"GGG has five days to decide which WBA title he's keeping if he beats Canelo on Sept. 17, a source told ESPN. If GGG remain at 160, or if he loses, he must defend his "super" middleweight title vs. secondary champ Erislandy Lara within 120 days of the fight," Coppinger wrote.
Earlier, QazMonitor reported that Golovkin and Canelo's third fight will take place in the super middleweight division: all of the Mexican's titles will be on the line.
The trilogy will take place at the T-Mobile Arena, which is the site of their previous two fights: the first (2017) ended in a controversial draw, and the second (2018) ended in a marginal victory for Canelo.