SAN DIEGO - Chargers safety Jahleel Addae didn't show symptoms of a concussion until Friday afternoon, a day after having two scary reactions following hits in a loss at Denver, a person with knowledge of the situation said.
The person spoke to The Associated Press on Saturday on condition of anonymity because of the sensitivity of the injury.
Addae's injury gained significant attention after he convulsed while remaining on his feet after a helmet-to-helmet hit late in the third quarter Thursday night. On the game's first play from scrimmage, Addae made a hit and immediately went limp on the ground.
Addae's reaction to the second hit caused a stir on Twitter. Many people wondered why he was allowed to remain the game and some compared it to when Chargers four-time Pro Bowl left guard Kris Dielman was staggered after sustaining a career-ending concussion in the sixth game of the 2011 season, at the New York Jets.
Dielman wasn't diagnosed with a concussion until after that game. He suffered a grand mal seizure on the flight home. The team plane was met by an ambulance and Dielman was hospitalized overnight.
Ten days after Dielman was hurt, the league's injury and safety panel told game officials to watch closely for concussion symptoms in players. Officials were told that if they believed a player had sustained a concussion, they were to take appropriate steps to alert the team and get medical attention for the player.
Dielman didn't return that season. The following March, he chose to retire rather than risk further damage.
George Atallah, the assistant executive director of external affairs for the NFLPA, said Saturday that the players' union is looking into the Chargers' handling of Addae "as we do with all player health and safety matters."
The person with knowledge of the situation said Addae was checked on the sideline after both hits and was cleared each time, and that he was checked after the game, with no symptoms of a concussion.
The person declined to say what symptoms Addae showed Friday afternoon.
Addae said after the game that he passed the NFL's concussion test. The team said then and again Friday afternoon that Addae had a stinger.
At a news conference Friday afternoon, coach Mike McCoy said the team followed proper medical procedure with Addae.
Asked to confirm there was no head trauma, McCoy responded by saying he had to meet with trainer James Collins. "I've said all I'm going to say about the whole football team with where we are right now," said McCoy, who loathes discussing injuries.
Addae was not in the locker room when it was opened to the media about an hour later. A team spokesman later said the safety went to get additional tests. A few hours after that, the team said Addae had been diagnosed with a concussion.
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