4:09 PM PT -- Myles Garrett is not backing down from claims Mason Rudolph hurled a racial slur at him during the helmet-throwing incident ... saying "I know what I heard."
Garrett just issued a statement ripping the NFL ... accusing league officials of leaking confidential information from his appeal hearing to the media.
Here's his statement in full ...
"I was assured that the hearing was space that afforded the opportunity to speak openly and honestly about the incident that led to my suspension," Garrett says. "This was not meant for public dissemination, nor was it a convenient attempt to justify my actions or restore my image in the eyes of those I disappointed."
"I know what I heard. Whether my opponent's comment was born out of frustration or ignorance, I cannot say. But his actions do not excuse my lack of restraint in the moment, and I truly regret the impact this has had on the league, the Browns and our devoted fans."
1:14 PM PT -- The NFL says it investigated Garrett's allegation and found "no such evidence" that Rudolph hurled a racial slur.
"We looked into it and found no such evidence," NFL spokesperson Brian McCarthy said.
Myles Garretttold NFL officials Steelers QB Mason Rudolph hurled a racial slur at him before the infamous helmet attack ... though Rudolph is calling BS.
As we previously reported, the Cleveland Browns star met with NFL officials to appeal the length of his suspension from the Nov. 14 incident.
During the meeting, Garrett told his side of the story ... and claimed it was a racial slur from Rudolph that got him so pissed off, he ripped off the QB's helmet and attacked him with it, according to ESPN's Adam Schefter.
But, Rudolph is VEHEMENTLY denying the claim -- his lawyer has already issued a statement calling the allegation a flat-out lie.
"This false allegation was never asserted by Garrett in the aftermath of the game, never suggested prior to the hearing, and conspicuously absent in the apology published by the Browns and adopted by Garrett."
"The malicious use of this wild and unfounded allegation is an assault on Mason's integrity which is far worse than the physical assault witnessed on Thursday."
"This is reckless and shameful."
Browns head coach Freddie Kitchens just addressed the situation at Browns practice on Thursday, saying, "I stand by Myles and that's not going to waver. I'll support Myles in every way possible."
Kitchens refused to disclose what he and Myles talked about following the incident.