Aaron Hernandez -- Blocked From Watching NFL in Jail

Aaron Hernandez wasn't watching when Tom Brady and his former Patriots teammates mounted a comeback against the Buffalo Bills this past weekend ... 'cause he's NOT allowed to watch football on TV during his stint behind bars, TMZ has learned.

Sheriff Hodgson of the Bristol County Jail tells us, "While Mr. Hernandez and many other inmates would like to watch football, it is just not part of our policy here ... so that will not be happening. “

Hernandez does have an hour of free time per day ... so, in theory, someone could call him on the phone and play the TV really loud so he can follow along with the action -- but what's the fun in that?