The victim, Derrick Jones, 24, of New York City, remained hospitalized Tuesday in critical condition at Harlem Hospital Center in Manhattan, Passaic Police Detective Andrew White said.
The Browns issued a brief statement Tuesday saying the team was "aware of the situation."
While at the University of Virginia, Walcott was briefly suspended from the football team after he was arrested and charged with assault after a fight near James Madison University,the Washington Post reported. The charges were dropped.
The 23-year-old Walcott was a standout player at Hackensack High School.