The New England Patriots fear Rob Gronkowski suffered a torn ACL in his right knee.
Gronkowski will undergo an MRI on Monday.
"Rob was taken to the hospital for observation and evaluation on his injury," Bill Belichick said. "That's all I have on it."
Gronkowski was hit in his right knee by Browns' safety T.J. Ward.
"It was a decision I made just to make a tackle on a big man and unfortunately he got hurt, but if I would've hit up high, there's a chance I would get fined and all that other stuff. I'm just being safe," Ward said.