Speaking to reporters in the lobby of the league's hotel, Mara, a member of the league's competition committee, cited data released in January that showed concussions were up by nearly 32 percent in the 2015 season as cause for greater urgency in what he called the NFL's quest to make its game safer.
"There's no secret that repeated concussions can have a very serious long-term effect [on players]," Mara said. "And I am startled to a certain extent by the rise in concussions this year because we were on a steady downward trend for the last three years, and all of a sudden they spiked up this year, and we're still trying to understand why that is.
"We understand more than we did years ago, but we're still not even close to having the knowledge that we need to have going forward. That's why we're spending millions of dollars in research and trying to understand more about this issue. That's why we have the leading experts, we think, in the country on our health and safety committee. So we have a long way to go on that issue."
NFL data showed 271 concussions diagnosed during the regular season and preseason in 2015, up from 206 in 2014, 229 in 2013 and 261 in 2012. Mara said the competition committee reviewed tape of nearly every concussion from the 2015 season in an attempt to reduce future occurrences. Although he maintained the recent admission by Jeff Miller, the NFL's senior vice president for health and safety policy, establishing a link between degenerative brain disorders and football "wasn't anything new, though I know it was portrayed that way," Mara said his fellow owners grasp the magnitude of the CTE crisis.
"I don't think we're hiding from it," he said. "I know a lot of people have accused us of hiding from it in the past, but I certainly don't think that's the case anymore. ... It's something we have to keep pouring money into and keep studying because it's not going away.
"You don't want to put your players at a greater risk than you already understand they're taking. You've got to do whatever you can to protect them. We need to understand why concussions are up because you hate to see it. It's the No. 1 challenge going forward, and everything else we talk about this week is secondary to that."
Mara also addressed the report in The Wall Street Journal that the league and the NFL Players Association are making progress on a deal that could strip commissioner Roger Goodell of his authority to discipline players under the personal conduct policy.
"We're still in the middle of discussions with the union about the personal conduct policy," Mara said. "We have a long way to go before we reach any type of agreement in that area. ... Could I see a scenario where some of those rules were changed by mutual agreement? Yes, I think that's possible. But we're a long ways off."
NFL VP: 'Certainly' a link between football, brain disease
ESPN investigative reporter Steve Fainaru discusses NFL vice president of health and safety Jeff Miller's admission of a link between football and brain trauma.