Prado left Miami's game against Washington after he pulled up limping while running out a grounder in the sixth inning.
"At first I thought it was something minor, but as I passed the base, slowing down, the pain was sharper and sharper," Prado said after the Marlins' 9-5 loss. "They just did an ultrasound and it showed something. There is a significant gap between the fibers and the muscles."
Hamstring and knee injuries limited Prado to 37 games last year, and he missed the first month of this season recovering from right knee surgery.
"It has been a difficult year and a half for me," said the 34-year-old infielder.
Prado had hits in his first three at-bats against Nationals ace Max Scherzer, and reached on an error when he was hurt. Miami manager Don Mattingly said Prado's latest injury was especially deflating for the Marlins.
"That's a tough one to watch, knowing what Martin has been through," Mattingly said. "You feel so much for him."