The National Football League seemed to promise a lawsuit against the New York Times if the newspaper did not retract its investigative article on the league's concussion research. The NFL indicated the Times reporters involved in the story should "preserve" any document relevant to the case.

The Times ran the story on the front page of the newspaper on Friday, March 25 and effectively accused the NFL of utilizing incomplete data on head trauma. Specifically, the Times alleged the NFL ignored more than 100 diagnosed concussions from research studies that deemphasized the dangers of head trauma and their relation to the game of football.

The article also contained allegations the NFL modeled its approach to the one Big Tobacco used to downplay the dangers of smoking cigarettes, though not just by copying and pasting. The Times found evidence the NFL consulted lawyers that had previously defended the tobacco industry in regards to growing concerns about head trauma.

Politico obtained a letter in which the NFL demanded the article be retracted and alluded to the newspaper's staff hanging onto any related files. Brad S. Karp, an attorney representing the NFL, wrote in the letter the Times' story was "false and defamatory."

The NFL initially responded by publishing an extensive statement, calling the newspaper on contradicting itself with a key disclaimer: "The Times has found no direct evidence that the league took its strategy from Big Tobacco." The NFL later paid to publish a promoted post on Twitter containing a link to their statement and then ran ads highlighting their response to CTE on the Times' website.

Jason Stallman, the Times' sports editor, responded by pointing out that the New York Giants have a part owner who also shares ownership of a tobacco company. He also highlighted the main finding: the 100+ ignored concussion diagnoses.

"Our reporting showed that more than 100 such concussions - including some sustained by star players - were not included in the [NFL's] data set, resulting in inaccurate findings," Stallman said in a statement.

Joe Lockhart, the NFL spokesman who authored the league's statement, stopped short of definitively promising a lawsuit if the Times declined to retract its article.

"We won't prejudge the reaction of The New York Times," he said. "We make a strong argument for a retraction, one we expect to them to take seriously."