RENTON – In discussing the recent on-field restraint of fiery offensive tackle Breno Giacomini, there are two things to consider.

First, this has been a long time coming. Offensive line coach Tom Cable said the staff has talked to Giacomini over the years “ ’til we’re blue in the face.” Second, Giacomini is not completely reformed. The nastiness that’s gotten him whistled for personal fouls in previous seasons is still there. He’s just trying to be smarter about picking his moments.

The net result: In two games, Giacomini has goaded two opponents into 15-yard personal-foul penalties while he has yet to pick one up.

“Let’s say this,” coach Pete Carroll said. “He’s been on both sides of the line, and he’s been on one side a lot more than he’s been on the side he’s presently operating at.”

He added, “We’re going to take this one game at a time with Breno. I wouldn’t say he’s arrived.”

Giacomini prides himself on playing right up until the whistle. He often got in trouble when he crossed that line. Against St. Louis last year, for example, Giacomini picked up two personal fouls when he ran toward the pile and hit defenders late.

This year, he’s consciously thinking about when he can deliver a hit around a moving pile and when he needs to hold back.

“Once I’m on that field, it’s a different me,” he said. “We try to be good guys off the field, but on the field I turn it up.

“That’s the switch I’ve learned to turn on and off, even on the field now. The switch on the field is the whistle, I guess. That switch of, ‘when is that guy going to blow that whistle?’ ”

Giacomini was one of the NFL’s most penalized players a year ago with 12 penalties. He’s been called for two penalties this season, both holds against the 49ers. He needs to clean those up, but one of the penalties he baited a San Francisco player into committing was critical.

On the final drive of the third quarter, with Seattle leading 12-3, the Seahawks kept moving backward. Because of a holding penalty and two straight plays that lost yards, Seattle faced a third-and-28. Giacomini squared off one-on-one against Aldon Smith, one of the NFL’s best pass-rushers, and kept him away from quarterback Russell Wilson.

After Wilson completed a 15-yard pass on the play, Giacomini swiped Smith’s hands off his chest. Smith retaliated by quickly shoving his right hand into Giacomini’s facemask. Giacomini threw up his hands, turned to the official and said, “Did you see that or not?”

On the NBC broadcast, analyst Cris Collinsworth started chuckling. “Breno Giacomini … has a way of irritating guys. (Smith’s) not the first one. And he who punches last usually gets caught in this league.”

Smith’s 15-yard penalty gave Seattle an automatic first down, and the Seahawks eventually scored a touchdown that gave them control of the game.

“He’s that edgy player on the offensive line,” Wilson said during training camp. “You need one of those. You’ve got to be careful having two of them, but you need one of them, for sure.”

Giacomini thinks he could be effective without the nasty streak that has earned him a reputation among other players. But that’s just not who he is.

“Never was,” he said. “Never will be.”

Center Max Unger said officials are closely monitoring guys running late to piles this year, so linemen need to draw a line. It’s one Giacomini will toe all season.

“Those guys don’t like me anyways,” Giacomini said after the 49ers game, “so when I get one, it feels good. But it’s still Week 2, you know what I mean?

“I’ve just got to keep playing smart.”

Jayson Jenks: 206-464-8277 or jjenks@seattletimes.com