Transcript for NFL's Low-Hit Rule Causing New Problems
Football is back and the nfl is paying close attention to tackles on the field. What they want to know is if encouraging players to hit low to avoid head injuries will now translate into a new set of concerns. Abc's gio benitez tonight, explaining why. Reporter: The debate is lighting up espn. Don't touch my knees. Just leave me alone. Hit me up high. Reporter: Two high profile players taking direct hits to the knee. Miami tight end dustin keller now out for the season, and minnesota defensive tackle kevin williams. And joe looney goes low. For no apparent reason. Now, you take a guy in the knee and you're watching a guy's knee completely fold back. Reporter: Potentially causing that debilitating knee injury, a torn acl. 24 during last year's preseason alone. But now people are concerned that perhaps this could be one of the worst seasons for torn ACLs. Well, I agree. Reporter: Why are we seeing so many knee injuries? Some say it's new nfl rules. Fining players for hits to the head. Which can cause concussions. Texans rookie, d.J. Swearinger, who hit miami's keller in the knee, told "the palm beach post," in this league, you've got to go low. If you go high, you're going to get a fine. This is the new nfl. You have to have a target on a guy. You have to hit a guy low. All right? That is the compromise. Reporter: An nfl official reportedly said the league will keep a close eye on hits to knees and could change the rules if the hits are, quote, becoming a problem. When you go low, the intention is never to take a guy's knee out. It's really to hit him in the thigh pad and there lies the problem. If you miss or the guy makes a move, then you hit him in the knee and the injury may occur. Reporter: Injuries that could take players out of the game for good. Gio benitez, abc news, new york.
This transcript has been automatically generated and may not be 100% accurate.