Anderson was hit by Giants defensive end Osi Umenyiora and landed on his head early in the second quarter of Cleveland's 37-34 defeat. The Browns described the injury Monday night as a "possible concussion"; Anderson's condition was later confirmed by a source.
There is still no official word on how much time Anderson might miss. The source says the concussion is not severe and, at the very least, Anderson should be ready for Cleveland's regular-season opener Sept. 7 against the Dallas Cowboys.
James Walker covers the NFL for ESPN.com.