SANTA CLARA — Quarterback Alex Smith is "just staying ready" in case the 49ers need him to reprise his role in Saturday's playoff opener against the Green Bay Packers.

Since sustaining a Nov. 11 concussion, Smith has been relegated to a backup role behind Colin Kaepernick.

"For me, it's just about being ready to go. My responsibility is to know the game plan and be ready," Smith said in an impromptu media session in the locker room. "You never know when your opportunity is going to come. The good ones are ready when it does."

That's sure held true with Kaepernick, a second-year quarterback who seized the starting role even after Smith was medically cleared to play two weeks after his concussion.

"Physically, he's a tremendous player, a guy that has a strong arm and can make all the throws," Smith said of Kaepernick, "What jumps out to me is how fast he can process things mentally. He's done a great job playing fast.

"I see more confidence from him, especially in times where it's grey and indecision. He makes a decision and goes with it."

Kaepernick completed 62.4 percent of his passes while totaling 10 touchdowns against three interceptions. Both he and Smith attempted 218 passes; Kaepernick completed 136 for 1,814 yards, Smith 153 for 1,737 yards.

A year ago, Smith was the one leading the 49ers into the playoffs, and he engineered an epic 36-32 triumph over the visiting New Orleans Saints in a Jan. 14 divisional-round game.

Smith described Kaepernick's demeanor as very unique and referred to how the Nevada product is often wearing headphones.

"The closer to game day, he keeps to himself and mentally prepares," Smith said. "He's making sure his mind is right, at least that's what I think he's doing.

"He's locked in."

Although he signed a three-year contract in March to return to the 49ers, Smith could be released without any serious financial impact before April 1, when he's due a $7.5 million roster bonus.

If offensive coordinator Greg Roman lands a head-coaching job, it's conceivable Smith could follow him there via a trade or as a free agent. Roman has college ties with the new general managers of the Jacksonville Jaguars and San Diego Chargers.

Smith declined to speculate on Roman's job possibilities but did speak fondly of the 49ers' second-year coordinator. Smith described Roman as "very pragmatic" who's team-oriented and willing to adapt to evolving situations.

"I've loved my time with him and he works so hard," Smith said. "With his knowledge, having coached both sides of the ball, I've learned a ton in the past two years. He's a special coach and I'm happy for any success he has."

Smith scoffed at the media's insatiable appetite to magnify the playoffs as well as any lack of production by receivers such as tight end Vernon Davis.

"It's still football. A lot of this is blown out of proportion, even though it's win or go home," Smith said. "A lot has been made about who gets the ball or not. As quarterbacks, we throw where we're supposed to. We have guidelines and reads. We're not sitting back there saying, 'Who do I want to throw to?' "

For more on the 49ers, see Cam Inman's Hot Read blog at blogs.mercurynews.com/49ers. Follow him on Twitter at twitter.com/CamInman.