Medvedev announces via his Instagram account that he has had problems with a hernia in recent months, which means that he is forced to have surgery.
“Together with my team, I have decided to make a small intervention to fix problems.
I will be away for 1-2 months and will work hard to be back as soon as possible ", he writes.
The upcoming grand slam tournament French Open starts on May 22 and if the rehabilitation drags on, the 26-year-old, who reached the quarterfinals last year, can miss the tournament.
Medvedev took over the place as world number one from Novak Djokovic at the end of February, but lost that place a little more than a week ago.
The 26-year-old was in the final of the Australian Open last winter and took his first grand slam title when he won the US Open in September.
CLIP: See the freak - after the crazy duel (April 1)
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The freak - after the crazy duel