Last week the New York Times released an explosive story on the NFL and concussion research, alleging the NFL's data omitted more than 100 concussions and linking the NFL to Big Tobacco.

This did not go over well with the NFL. But the league took it a step further Tuesday, sending a letter from the Ted Wells' law firm (yes that Ted Wells) demanding a retraction from the Times and potentially setting the deck for a lawsuit. 

Politico first reported the news and posted the letter on its website.

Accordingly, we demand that the story immediately be retracted, and we reserve our rights more broadly. We also request that the Times's reporters and editors who worked on this story preserve their notes, correspondence, emails, recordings and work papers and all other electronic and hard copy documents generated or received in connection with their work.

The "preserve your work" request coming from a law firm certainly sets the table for the NFL to later sue the paper, although quite often such requests are made by lawyers in order to leverage what they want now.

Put more simply, the NFL is basically saying "retract or we'll sue." It's a threat and there's no telling how serious it really is.

The biggest issue for the league is not the discussion of concussions, though. It's the connection to Big Tobacco. 

Trumpeting a connection between the NFL and the tobacco industry should require substantial, concrete evidence. In fact, the Times conceded that it found "no direct evidence that the League took its strategy from Big Tobacco."

The Times most certainly admitted there was "no direct evidence" involved in the discussion. 

But the league is not happy about the concussion charge either, throwing around the word "defamatory."

The story is false and defamatory on this point as well. There is not a single fact in the Times article that supports the allegation that the NFL intentionally concealed concussion data in a manner "parallel to tobacco research," as the revised Times print headline asserts.

Again, everything in this letter implies the NFL would consider/will consider suing the Times. One of the primary issues with filing a lawsuit is discovery. If you sue someone, you have to be prepared for everything related to the issue at hand to become public record if the lawsuit proceeds to the full extent.

It's hard to imagine the NFL wanting a lawsuit about concussions going public. 

Troy Aikman's concussions were not included in the NFL research according to the Times(Getty)