Johnson told the Detroit Free Press he suffered a concussion on a helmet-to-helmet hit from Chad Greenway. Johnson was slow to get up and was tested for a concussion on the sideline.
"Yeah, yeah, he knocked me good," Johnson told the Free Press. "You could tell. It was obvious."
Lions coach Jim Schwartz said Johnson cleared the concussion test, and therefore was allowed to return to the game, according to the report.
"Our evaluation was that he was not concussed," Schwartz told the Free Press. "He was thoroughly checked. We're very strong in our evaluation. He was cleared to go back in the game, and he was on a protocol after that, and he was cleared then. We're very strong in our evaluation, and we are, as an organization, I think we have some credibility when it comes to concussions."
According to NFL protocol, a player suspected of having a concussion must be tested by medical personnel. If a concussion is diagnosed, the player is then removed from the sideline and can't return to the game.
Johnson, in a Thursday interview with WXYT-FM (97.1) in Detroit, said playing with concussions is simply a part of the game.
"It's a part of football," Johnson said. "You get concussed, you gotta keep on playing."
Johnson later clarified those comments, stating he actually meant that, as a receiver, he can't be scared to go over the middle.
"Not that if you're concussed that you've got to keep playing," Johnson said following practice. "We know we can't do that if we don't pass the test. I was just saying that you can't be afraid to keep on going over the middle and doing what we've been doing."