The NFL followed all normal protocols in investigating Browns defensive lineman Myles Garrett's claims that Steelers quarterback Mason Rudolph used a racial slur against him during their fight in Week 11, according to sources with knowledge of the situation, including attempts to procure any audio at the scene and conferring with in-game officials as well.

Garrett, an elite pass rusher who was the first-overall pick in 2017,  was suspended for at least the remainder of this season for removing Rudolph's helmet and then smashing him in the head with it. Rudolph was fined for his actions during the interaction, yanking on Garrett's helmet and facemask and trying to strike him with his hands and feet as well. Garrett alleged, during the appeals process last week, that Rudolph had also used a racial slur on the field, which the league looked into as it would in any instance of allegations of this sort.

Garrett is required to schedule a meeting with officials from the NFL and NFLPA after the season as part of the parameters of his suspension. League sources said there is no consideration at this point that his discipline should extend into 2020, but rather, given the violent nature of this act, both parties wanted to have a "check-in" discussion with Garrett as a stipulation of his return.

"That shouldn't be read as a threat that this will carry over into 2020," said one source with knowledge of the situation, "but given the level of violence that was displayed it's important that he make the effort to check back in with the NFL and NFLPA and discuss things with them."

While there were microphones around the offensive linemen in that Thursday night game, they were being used for ambient sound (grunting and noises pre-snap, calling out audibles, etc.) but not for any individual player on that group being miked for sound to be used later. The mics that FOX used during that broadcast, being run by NFL Films technicians, are to be shut off at a certain point and are not to be used or distributed in any other fashion, sources said.

The game report filed by the on-field officials working that night did not indicate anyone on the field heard any improper language and there was nothing reported to the on-field officials at the time, or after the game, sources said. The NFL monitored the social media of Garrett and his friends, family and teammates -- as they would any player making such allegations -- looking for corroborating evidence. Furthermore, the Browns did not privately report any of the allegations or concerns to the league, sources said, nor was there any indication of any offensive language being used in their public statements on the matter, including from ownership in condemning Garrett's actions. There were also no corroborating statements.

"We could find no such evidence," NFL spokesman Brian McCarthy said.

Steelers team officials, first hearing notice that Garrett might be making such claims in his appeal process, could find no corroboration from their players, many of whom they believe would have taken issue with a teammate saying anything offensive. Former NFL player James Thrash, hired jointly by the NFL and NFLPA, made the final decision on the appeal, upholding the league's decision.

"This decision is final," as one NFL source put it, "and it was made by his peers. His peers heard all the evidence as appeal's officers and they made the decision that this is unacceptable. They've seen and heard it all, and their decision is final."