By Steve Ginsburg
(Reuters) - The National Football League said on Monday it was investigating as to why St. Louis Rams quarterback Case Keenum was not tested for a possible concussion after smacking his head on the turf in Sunday's game and staggering to get to his feet.
When he was tackled by Baltimore Ravens' 300-pound (136 kg) defensive lineman Timmy Jernigan, Keenum immediately held his head before managing to get to his knees while game officials sorted out a penalty.
St. Louis's backup quarterback Nick Foles put his helmet on and began warming up, but a wobbly Keenum managed to stand up and stay in the game. Two plays later, Keenum fumbled, a crucial late-game turnover that enabled the Ravens to win the game, 16-13.
Keenum, 27, was diagnosed with a concussion shortly after the game ended.
The NFL said on Monday it began a review on Sunday why Keenum was not taken off the field for "the necessary evaluation" by a team doctor or the independent neuro-trauma physician as required by its concussion protocols.
"We are continuing that review today, which includes discussions with the Rams and their medical staff, the ATC spotter, the game officials, our medical advisors and the NFLPA," the league said.
"In the meantime, prior to this week's games, we will reinforce with all involved the need to ensure that these injuries are properly identified and addressed in a manner consistent with our protocols."
The NFL this year gave independent certified athletic trainers, or ATC spotters, the power to stop play to remove from the field players potentially suffering from concussions.
But that was not implemented on Sunday in Baltimore.
Neither the Rams nor the NFL Players Union responded to a request for comment.
The NFL and more than 5,000 former players agreed to a settlement of concussion-related lawsuits in April that could cost the league $1 billion, if approved. The players claimed the league hid the risk of concussions.
(Reporting by Steve Ginsburg in Washington, editing by G Crosse)