Vitali Klitschko could finish his boxing career in September if he is elected to the Ukrainian parliament.
The WBC heavyweight champion, 40, faces undefeated German Manuel Charr in Moscow on 8 September.
But he is standing for election the following month, meaning the Charr meeting could be his final bout.
"Holding a political office and being heavyweight champion at the same time are not compatible," said the former Kiev mayoral candidate.
"Depending on the outcome of the elections, I will decide on the future of my sporting career."
Klitschko, whose younger brother Wladimir holds the IBF, IBO, WBA and WBO belts, has won 44 of his 46 career fights, most recently securing a points win over Briton Dereck Chisora in February.