WBC heavyweight champion Vitali Klitschko has revealed that he is considering hanging up his gloves.
The news that Klitschko is pondering retirement is a further blow to British rival David Haye's slim hopes of securing a unification clash with the Ukrainian.
"I feel like a 25-year-old but on paper I'm a boxing grandpa; I'm well aware of that," said the 39-year-old, who faces Odlanier Solis in Cologne on March 19. "Lots of sportsmen have missed the right moment to end their career. That's not going to happen with me.
"Every fight carries with it a big risk. You have to be realistic. But there will be a couple of fights yet.
"I have always said I want to face the best in the world. I want to show that I am No.1 in the world. This Solis will not be a walk in the park. He is a good young boxer, but he misses the experience which is important in the world of boxing."
Former Olympic heavyweight champion, Solis, 30, has a perfect record of 17 wins, 12 knockouts and no defeats, while Klitschko will be making the sixth defence of the heavyweight title he won by defeating Nigeria's Samuel Peter in Berlin in October 2008.