It was an accident. Quintin Mikell, trying to keep Hank Baskett out of the end zone, slipped his hand inside the back of Baskett's shoulder pads and yanked him down from behind.

In a game, that play would have earned Mikell a 15-yard penalty for unnecessary roughness for a horse-collar tackle. During training camp, it earned him a tongue-lashing from defensive coordinator Jim Johnson.

"I got a stern talking-to," Mikell said last week. "He was right. Especially in training camp, you don't want to hurt your own player. First of all, you don't want to be known as a cheap shot, and you don't want to be known as someone who is out there to deliberately hurt people."

Anyone who repeatedly makes the dangerous horse-collar tackle, banned by the NFL on May 24, 2005, by a 27-5 vote, becomes known as Dallas safety Roy Williams. The rule, after all, was adopted because of him.

For the third time this season, Williams pulled a player down by the back of his shoulder pads. Last week, that player was Donovan McNabb. The Eagles breathed a collective sigh of relief when McNabb bounced up off the turf after the awkward hit. With McNabb scrambling for a 17-yard gain in the first quarter of the Eagles' eventual 10-6 win over the Cowboys, Williams caught McNabb from behind - which was bad enough - and tried to swipe at McNabb's lower leg.

The result could have been disastrous. McNabb could have broken an ankle, as Terrell Owens did late in the 2004 season when Williams pulled down the receiver, then playing for the Eagles. McNabb could have torn cartilage in one knee and sprained a ligament in his other, as Tennessee wide receiver Tyrone Calico did in a preseason game in 2004, thanks to Williams. McNabb could have snapped his tibia, as Baltimore running back Musa Smith did, or sprained an ankle, as Jamal Lewis did, both thanks to Williams - in the same game.

Or, it could have been worse.

The National Football League suspended Williams without pay for the Cowboys' game last night against Carolina. The suspension cost Williams $35,000, as well as his streak of 94 consecutive games played. Williams appealed the suspension, but the league denied it.

Dallas coach Wade Phillips' take on the suspension: "He didn't hurt anybody."

Williams' hit on McNabb was his third horse-collar infraction this season. The first, delivered on Chicago tight end Desmond Clark, cost Williams $12,500. The second, on Buffalo running back Marshawn Lynch, cost him $15,000, plus a letter of reprimand.

The hits to Williams' reputation have been more severe. He's an aggressive safety, yes, but he's also frequently out of position, unable to bring down the offensive player in a traditional manner.

"After the game, he apologized and just told me that he wasn't trying to hurt me in any way," McNabb said last week. "I know Roy. Roy wouldn't try to hurt anybody. [He was] just trying to make a tackle. He's one of the best safeties in the game, but, pretty much, that's what he's known for: the Cowboy tackle, or whatever they call it."

Owens, now Williams' teammate in Dallas, said last week: "To get tackled like that, and I got hurt, it was very excruciating pain. If you've never experienced it, then you are, 'OK, it's just a tackle.' It's a dangerous tackle. Roy has his way of tackling people, and it's unfortunate the way he tackles, because it's very, very dangerous. . . . I think he needs to do something to kind of correct that. Roy's a great guy, but you have to be safe. To tackle someone in that manner is just not right."

A horse-collar tackle is dangerous because the player being tackled is pulled from behind. The force of the defender's weight, coupled with the forward motion of the offensive player, can snap bones, tendons, or worse. The offensive player also is vulnerable in the midsection, especially if he has lowered his shoulder to deliver a hit on a defender in front of him.

"It is dangerous," McNabb said. "I've seen it firsthand happen to T.O. I remember when it happened. I actually thought it was worse than what it was, [worse] than a broken ankle.

"It's a play where you're kind of defenseless. You think you've passed a guy, and then all of the sudden he yanks you back. Your feet are under you, you get bent back in an awkward position, and anything could break."

In 2005, only one penalty was called for a horse-collar tackle and only two fines issued.

Last season, referees called 14 horse-collar penalties, and the league dished out 29 fines, including one to Williams.

This season: nine penalties and 24 fines.

Baskett remembers the dangerous play in training camp. He also remembers when it happened to him in high school, when Baskett was a quarterback, and once in college.

"It's going to hurt, no matter what," Baskett said.

When Mikell did it in practice, Baskett had caught an underneath pass and gotten an angle on the safety. Baskett turned upfield "faster than I thought he was going to," Mikell said. Surprised, Mikell admitted he went into "panic mode."

Although there was no real harm done, Mikell learned his lesson. His coach made sure of it.

"It's hard sometimes," Mikell said. "As a defensive player, you kind of feel like if you let him go, then you're going to look bad. It happens."

Contact staff writer Ashley Fox

at 215-854-5064 or afox@phillynews.com.