WASHINGTON -- NFL commissioner Roger Goodell has a message for anyone wondering whether his sport is worse off because of an increased emphasis on eliminating violent hits: We're doing fine, thanks.

"People have criticized us as changing the game," Goodell said Monday. "I don't believe that. I think we have taken techniques out of the game and improved the game and made it safer -- and the game's more popular than ever."

Goodell met with about a half-dozen reporters after delivering a speech about concussions at the Congress of Neurological Surgeons. He told the gathering of doctors that the NFL and the players' union jointly have committed to spending $100 million over the next 10 years on medical research -- "the vast majority" on brain injury research.

He also told the group: "If there is any suspicion about a player being concussed, he should be removed from the game. Period. This is consistent with our policy that medical considerations must steer the ship and always override competitive concerns."

Afterward, Goodell told reporters the NFL has "made tremendous progress" in the area of head injuries, "and it comes in a variety of different ways, and overall it's about changing the culture, not just in the NFL."

One way that change is seen, according to Goodell: Players increasingly are pointing out teammates who have concussion symptoms.

Another way: different tackling.

"Players really are playing the game differently. They're using their shoulders; they're not using their head. And I think they're having the same impact on either tackling or separating the ball in the case of a pass play," Goodell said.

"You're always going to have individuals that are going to, maybe, go outside the rules -- but they know we're watching, and they know that it's not in their best interest from a health standpoint," he continued. "So the fact is, it's not good for them as the one who's doing the striking as well as the person who is struck."

Goodell said the last report he received about NFL concussions covered only exhibition games -- and it showed the number of players' head injuries "were roughly consistent" with the 2010 preseason.

He thinks it's too soon -- four weeks into the regular season -- to judge what impact the new kickoff rules might be having in cutting down on head injuries. Goodell also said it makes sense to wait to decide whether rules in the new collective bargaining agreement cutting down on full-contact practices are having any effect.

As for future advancements, Goodell said the elimination of three-point stances for linemen in order to cut down on helmet-to-helmet contact will "continue to get evaluated."

The league's competition committee and other panels have discussed that possibility "a fair amount," Goodell said, but "they just haven't felt that it was a significant move that was going to really change the game from a health and safety standpoint right now."

Similarly, the league has "done a number of research studies" to determine whether wearing mouthpieces can help players, and that work "has not proven, to date, that they are significant in preventing concussions," Goodell said.

Before Goodell's speech to the neurological surgeons, Dr. Richard Ellenbogen, a co-chairman of the NFL's head, neck and spine committee, told the group about the NFL's work with the federal Centers for Disease Control and Prevention in formulating an online educational toolkit to help diagnose and manage concussions. The toolkit will be available on the CDC's website later this week.