Jared Fogle was almost guaranteed a beatdown in prison, because guards made it clear to the other inmates he was the teacher's pet.
We've learned prison staff told the inmates before Fogle arrived at Englewood Correctional facility that he would be arriving in late December and that no one should mess with him.
Our sources say the staff made it clear ... anyone who attacked or harassed Fogle would be dealt with harshly.
That was enough for Steven Nigg, the 60-year-old inmate who beat Fogle up weeks after his arrival. We're told Nigg resented Fogle because the staff made him seem "untouchable" ... so he touched him.
TMZ broke the story -- Jared was pushed to the ground and beaten back in January. Steven Nigg was thrown in solitary for the attack.