On Tuesday, the NFL sent a memo to clubs saying they are no longer allowed to provide the substance to players, citing safety concerns. Here's what experts say about the effects and the risks.
Tua Tagovailoa sustained a major hit in a Sept. 25 game that the team called a back injury that raised questions. Now, he's being treated for a possible concussion after a Thursday game.
A concussion can make it difficult to converse in a noisy room. Scientists say that's because the injury has impaired the brain's ability to process sounds.
