SANTA CLARA -- While Patrick Willis wracked up 171 regular-season tackles en route to his sixth straight Pro Bowl honors, he got penalized only once -- for holding.

Willis plays the game clean. Yet he shakes his head at the prospect of adjusting to the league's increasing emphasis on safety.

"That's a sensitive subject when it comes to me," Willis said Wednesday. "I love to play this game and always want to play defense, for the simple fact you can hit and let loose and not get penalized for the way you attack them.

"Now you have to be conscious of it. I always want to play within rules. I'm not going to lie to you: If I can get zero-in shots like safeties get ... I never get that chance to hit straight on."

Willis' next opportunity will be Sunday, when the 49ers visit the Atlanta Falcons for the NFC Championship.

Willis, who earned AP All-Pro First Team honors last weekend, scoffed at the notion defenders have enough time to react and "duck" to avoid such illegal contact as helmet-to-helmet hits. Safety Dashon Goldson drew such a penalty in the 49ers' playoff-opening win Saturday over the Green Bay Packers.

"I'm going to hit and I hope it's within the rules," Willis said. "If I ever get flagged, it doesn't mean I do it intentionally. My job is to make tackles."