USA Today

The entire NFL came to a screeching halt when it happened. Patrick Mahomes, the former league MVP and reigning Super Bowl MVP, scooted to his right for a routine option play with the hopes of gaining a couple of yards for a key first down against the Cleveland Browns in the AFC Divisional Round. There was nothing routine about the outcome though, with the Kansas City Chiefs seeing the head of their half a billion dollar investment driven to the grass -- followed by a scary moment when Mahomes attempted to and failing to stand on his own. 

The clearly woozy franchise quarterback was completely out of sorts and was helped to the medical tent before then going into the locker room, where he was almost immediately ruled out for the remainder of the game. Following the game, head coach Andy Reid made it clear Mahomes passed the league's concussion protocol, which is good sign No. 1 for his availability going forward.

"He got hit in the back of the head and kinda knocked the wind out of him and everything else with it," Reid said. "He's doing great right now which is a real positive as we looked at this. Passed all the deals that he needed to pass so we'll see where it goes from here."

Mahomes took to Twitter to add more optimism, replying to linebacker Mack Wilson, the Browns defender who tackled him on the ill-fated play.

So if Mahomes passed all of the concussion tests, what exactly did happen that prevented him from returning with everything on the line against Cleveland? It turns out Mahomes easily passed the concussion tests because he reportedly never had one in the first place, and the actual reason he was instantly delirious was reportedly due to a nerve in his neck that got tweaked (or potentially compressed) on the hit, per Carrington Harrison of CBS Sports Radio in Kansas City. 

This means, while there's great news regarding the condition of his brain, he'll still undergo tests this week on the affected nerve to make sure he's allowed a green light against the Buffalo Bills in the AFC title game (here's a look at what he'll have to do to be able to play). The Chiefs might've gone on to win in the absence of Mahomes, thanks to the heroics of backup quarterback Chad Henne and outlandishly provocative play-calling from offensive coordinator Eric Bieniemy, but Kansas City will need Mahomes on the field to increase its chances of staving off the equally high-powered Bills for a second consecutive trip to the Super Bowl.

It goes without saying that this is the headline to watch this week, as Reid confirmed on Monday that Mahomes is indeed in concussion protocol this week, even though he's not failed any of those tests.