The 28-year-old tried to beat a relay at first and his foot landed on the cushion on Friday in the ninth inning against the New York Mets.
Eaton fell to the ground and he needed help to leave the field.
“It’s probably the worst pain I’ve ever felt in my life,” Eaton said. “When I heard it pop I thought it was my ankle, and it was my ACL it wasn’t my ankle. I looked down to basically see if I saw any bones and make sure that everything’s still there.”
The center fielder maintained an average of, 297 with two circuits and 13 points produced this season. He has traveled on the trails in 20 of the 23 games with the Nationals, since he was acquired from the Chicago White Sox during the offseason.
General manager Mike Rizzo said Eaton has a “full thickness” ACL tear, plus a meniscus tear and a high ankle sprain.
“His return to this season is unlikely, but we don’t know until the doctors get in there and we’ll see what the surgery leads us to believe,” said Rizzo, who added the surgery date is not set.
Short-stopping player Trea Turner will now be the first Nationals hitter and Michael A. Taylor will replace Eaton at the center field.
The Nationals also recalled the outfielder Rafael Bautista from their AAA-rated school club.