Medvedev joins growing list of injured names ahead of French Open
The Russian had treatment on the upper part of his right leg while leading Czech Jiri Lehecka 3-2 in the first set and again two games later. He went on to lose the set 6-4 before telling the umpire he could not continue.
"It was a return when he served and volleyed and I don't know if I felt it on the return or on the drop shot, but when I ran, I wanted to run faster and faster during the movement, and suddenly felt my hip blocked," Medvedev said.
"I couldn't sprint, like when you strain a muscle or have a spasm, which is tough to know which of the two. Working with the physio, I asked if I could make it worse. He said 'if it's a tear, then yes. If it's a spasm, no'.
"I tried to play and my mind wasn't letting me to go full. At the end of the set, I was (thinking) if I want to continue, I'll just try to sprint to the net... When I sprinted I felt pain. So I was like: no need to continue."
Medvedev is the latest high-profile player to exit the tournament after Australian Open champion Jannik Sinner pulled out before his quarter-final against Felix Auger-Aliassime due to a hip injury.
World number three Carlos Alcaraz lost his quarter-final to Andrey Rublev while managing a right forearm problem that had forced him out of Monte Carlo and Barcelona.
Medvedev is scheduled to defend his Rome title next week but he said he had no idea how long he could be out for.
"Hopefully for sure tomorrow or day after, because normally you need time, MRI to see what it is, and if it's something five days, two weeks, I have no idea."
The French Open begins on May 26th.