In posts on his Snapchat (via TMZ Sports), Barr relayed photos of a profane letter sent to him.
"Proud of yourself? You're a piece of s--t," one letter read. "You didn't have to throw him to the ground and purposely come down on top of him. Did you jump for joy when [you] heard his [collarbone] crack?"
The letter continued: "SOB bastard. Come 12/23, hope you get your neck snapped. Remember Darryl Stingley? Your payback is coming. Piece of s--t."
Barr is likely to receive something of an unpleasant welcome when the Vikings head to Lambeau Field to square off against the Packers in Week 16.
Not only did Barr send Rodgers to injured reserve for eight weeks, but the Packers quarterback told Conan O'Brien the Vikings linebacker had some words for him as he went to the sideline.
"I looked over at him as I walked off the field," Rodgers said. "Cameras caught me saying something to him but what they missed was him [giving me the] finger [and the] 'suck it' sign."
Barr later explained the account from his perspective in a message that was posted on Twitter and subsequently deleted.
"Smh this guy got y'all fooled man," Barr wrote, per the Star Tribune's Ben Goessling. "After the play, I go back to the huddle, don't even look or say a word to him. Once he gets up, I'm waiting for the play call, and hear someone shouting all kinds of profanities. I look over and it's y'all mans calling me all kinds of names, F you this, F you that as he's walking off the field. So naturally, I responded. I don't care if you Aaron Rodgers or Mr. Rodgers, if you say something like that you're gonna get a response from me."
Rodgers is expected to make his first start on Sunday, against the Carolina Panthers, since breaking his collarbone. He will get a shot at redemption against Barr and the Vikings Dec. 23, as the Packers attempt to run the table and sneak into the playoffs.