Sorensen was immobilized and taken to a hospital after a violent helmet-to-helmet collision in Saturday's loss to the Lions.
Coach Eric Mangini said initial tests on Sorensen were negative but the 10-year veteran and special teams standout will be "resting for a while."
Browns defensive back Ray Ventrone said Sorensen's injury "gave us a scare" but the team was relieved to learn he was doing better.
Sorensen appeared in all 16 games for Cleveland last season. He also plays on the kickoff return unit, which was the NFL's best in 2009.