Hawkins was admitted to the University of Pittsburgh Medical Center on Sunday after suffering a concussion from a blow to the head late in his team's 30-9 loss to the Pittsburgh Steelers.
He was hit after a fourth-down Johnny Manziel pass was intercepted at the 1-yard line by Steelers safety Mike Mitchell. As Hawkins moved to make the tackle, he was hit high and hard by linebacker Jarvis Jones.
Browns wide receiver Travis Benjamin said Jones' hit was "unacceptable."
"When he left his feet and kind of launched into Hawk, he could have easily just passed by," Benjamin said. "But it's the game of football. Those guys are looking to take our heads off and it's the same thing towards us."
The hit could be reviewed by the league because of the violent way Jones hit Hawkins' helmet.
This is Hawkins' second concussion over the past month. The fifth-year receiver had missed the Browns' previous two games after being diagnosed with a concussion late in a loss to the St. Louis Rams on Oct. 25.
He had been cleared to return for the Pittsburgh game and recorded seven receptions for 69 yards before the injury.
Hawkins' brother Artrell Hawkins Jr. posted on Facebook that Andrew "has no memory of what happened and is very confused."
Information from The Associated Press contributed to this report.