Medvedev, who beat Novak Djokovic in last month’s Flushing Meadows final to claim his maiden Grand Slam title, crashed out in the fourth round at Indian Wells this week, losing to Bulgaria’s Grigor Dimitrov.
“The tournament in Moscow is a special opportunity to play at home with Russian fans. I entered the tournament and hoped to play it, but due to such a busy schedule of tournaments in 2021, I felt that I was not ready to physically play 100%,” said the world number two.
“This decision was hard for me, but I had to make it in order to finish the season with good results.”
US Open women’s winner Emma Raducanu pulled out of the event on Thursday.