Update: Johnson said Thursday that he suffered a concussion as a result of a helmet-to-helmet hit that he absorbed in Week 4's contest against the Vikings, the Detroit Free Press reports.
Recommendation: Johnson, who was rocked by a Chad Greenway hit in the fourth quarter of the game, went through a series of tests on the sidelines and subsequently returned to the contest, but he evidently had his bell rung. In any case, while hearing that Johnson might have been concussed the last time he played is not optimal, he is not even listed on the Lions' Week 6 injury report, following the team's bye week.
