Young is scheduled to undergo more testing on the injury.
Young suffered the injury with 7 minutes, 49 seconds left in the second quarter when he rushed quarterback Tom Brady on third-and-2. Young went to the ground without much contact and writhed in pain.
When the cart came onto the field, Young waved it off and opted to limp more than 30 yards to the tunnel, with the help of teammate Brandon Scherff for part of the walk and then with trainers.
Young returned to the sideline in the second half on crutches.
Washington was already down one starting defensive end, as Montez Sweat suffered a broken jaw on Oct. 31 at Denver. Sweat will miss four to six weeks.
Young has not had the season he or Washington hoped, as he has just 1.5 sacks — one year after being named Defensive Rookie of the Year with 7.5 sacks. Washington coach Ron Rivera has harped on Young needing to be more disciplined as a pass-rusher, both with his technique and with his approach.
This past week, Young, the No. 2 pick in the 2020 draft, said he was not bothered by criticism of his play from the outside.
“I’m a man, I can take the criticism,” Young said. “It’s a process. Everybody will talk. Just wait until down the road. Just keep watching.”
ESPN’s Jeremy Fowler contributed to this report.