Gronkowski went down during the second half of the Patriots' 23-20 win over the Baltimore Ravens in the AFC Championship Game after getting hit by Ravens safety Bernard Pollard. Gronkowski briefly went into the Pats' locker room after the injury, but quickly returned to the game. He was spotted after the game sporting a walking boot on his injured left leg.
According to The Boston Globe, Gronkowski will likely need surgery to clean up the ankle after the season.
"I'm not going to try to forecast where things will be 10 days from now," Belichick said.
The Associated Press contributed to this report