Spokesman Greg Aiello said the NFL is aware of the death threat and "our security staff has followed up with the Jets to assist."
But the disgruntled, "die-hard" Jets fan told Newsday Tuesday night that he never intended to carry out his threat against Sanchez.
"Hello I just want to confirm I do not have any intentions of harming Mark Sanchez or do I intend to do so," he wrote in an all-caps email. "I am deeply sorry that is has gotten this big and do not want it to get any bigger.
"I do not even own a gun"