There are not many guys in Walpole or Shirley who have killed at least 3 people by the age of 23, weigh 240lbs and have played the most violent sport in the world at the highest level. I think the people around Hernandez are in a lot more danger than he is.
Between 2001-2011 there were 2 prison murders in the MA prison system, I think that the badassness of the MA prison system is greatly exaggerated. CA had 142 murders during that same period of time, if he was doing time there I would agree with the suggestion but he is not a skinner so I do not see anyone gunning for him just because he played football. Sports ability is still applicable in jail, and Hernandez is great at football and basketball.