Detroit Lions head coach Jim Schwartz spoke Monday on many things, one of which was the injury sustained by running back Jahvid Best in Sunday’s game against the San Francisco 49ers. Best left the game in the fourth quarter and reports trickled out after the game that Best had suffered a concussion. Via the Lions Twitter:Schwartz on Best: “he started experiencing concussion-like symptoms after the game.” It’s the second concussion for Best this season; he experienced his first in the preseason. Injury concerns have always been the biggest knock on Best, who played in all 16 games last year, but was constantly on the injury report with a turf toe. Concussion concerns are a lot more serious, especially because his concussion in the preseason wasn’t his first overall.Best suffered a pretty serious concussion in college at Cal, where he went up trying to score a touchdown and flipped over onto his head, popping his helmet off and instantly showing signs of being concussed. There’s a video of it here, and seeing him on the ground like that is worrying stuff.Now with this concussion following the 49ers game, Best will not only have to pass the tests to get back in action, but he’ll need to evaluate whether or not he personally feels ready to get back in a game situation, as one of the scarier injuries in sports is a concussion.