Tom Pelissero and Lindsay H. Jones

USA TODAY Sports

DENVER - DeMarcus Ware had heard about former Dallas Cowboys teammate Sean Lee's knee injury before Ware began his first offseason practice with the Denver Broncos on Wednesday.

And Ware said the Broncos will be cautious to avoid a similar fate befalling one of their own star players in the non-contact sessions all NFL teams are going through the next several weeks – even though the reality is injuries like Lee's often aren't anyone's fault.

"First of all, as players, we're really concerned," said Ware, the veteran pass rusher who signed with Denver after the Cowboys cut him in March. "In the first meeting we had here this morning, we said we're thinking about our health.

"We're not trying to go as hard. It's not like you have pads on. It's just about taking care of each other, but being able to get your mental reps in. You're still trying to be physical, but having the right technique."

That's probably what Lee was focused on when he tried to plant before being blocked by rookie first-round pick Zack Martin on a screen pass in Tuesday's organized team activity (OTA) practice and tore the anterior cruciate ligament in his left knee.

Dr. David J. Chao, the former team physician for the San Diego Chargers, told USA TODAY Sports after reviewing video of the play it appeared Lee's injury happened before Martin touched him – a non-contact injury, which is how most ACL tears occur.

Chicago Bears receiver Domenik Hixon posted on Facebook that he, too, suffered an ACL tear Tuesday. Chargers linebacker Melvin Ingram was among at least a handful of players to suffer torn ACLs during OTAs in 2013, long before the pads go on in training camp.

"That's what happens when you have guys flying around at high speeds," Chao said, "and that's what OTAs are – fly around at high speeds, but don't hit anybody."

It's in the rules set forth by Article 21, Section 2(b)(iii) of the collective bargaining agreement, which says among other restrictions that players cannot be in shells or pads and "(n)o live contact is permitted."

The NFL Players Association has been in touch with Cowboys players about Lee's injury. If a violation is suspected, the union could file a complaint with the NFL. But it's not as clear-cut a situation as, say, coaches keeping players on the field longer than is permissible.

"It looks to me that Sean Lee injured his knee in a standard, non-contact drill and it wasn't the contact from Zach Martin that did it," Chao said. "Statistically, there's likely to be another one in OTAs, although who knows? Maybe everyone will be really careful now."

If there's an upside of getting hurt in May, it's this: thanks to advances in surgery and rehabilitation, there's a chance a player might not miss the entire season even after an ACL tear. Ingram suffered his injury May 14, 2013, and returned to make his NFL game debut Dec. 8.

Of course, that's not part of any coach's pitch this time of year. They'd just prefer players stay off the ground.

"We talk about, when you're practicing against each other being smart, trying not to finish," Broncos coach John Fox said. "You've got four (preseason) games to work on your finish against opponents. It's something you try to avoid, but no matter how hard you try, it happens."

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