The Washington Nationals confirmed on Sunday that center fielder Adam Eaton's season is likely over after tearing a ligament in his left knee.

General manager Mike Rizzo said Eaton has a "full thickness" ACL tear, plus a meniscus tear and a high ankle sprain.

In Friday's 7-5 loss to the visiting New York Mets, the 28-year-old Eaton stepped awkwardly on the bag when he beat out a throw to first in the ninth inning.

He fell down and then needed assistance leaving the field, keeping weight off his left leg.

Eaton, who went on the 10-day disabled list Saturday, was Washington's biggest offseason acquisition, arriving from the Chicago White Sox in a trade that included the Nationals' top two pitching prospects plus a 2016 first-round draft choice.