Kucherov blocked a heavy one-timer from Capitals defenseman John Carlson and looked to be in pain while hobbling to the dressing room.
Head coach John Cooper didn't offer an update on his blue-chip winger's status following the game, according to the team.
Kucherov recorded one assist and two shots on goal through 11:47 of ice time before departing.
The 26-year-old sniper entered Saturday's action with 10 goals and a team-leading 33 points in 29 games this season.
Kucherov authored one of the best campaigns in recent memory in 2018-19, leading the NHL with 128 points to capture both the Art Ross and Hart trophies.