METAIRIE — When the New Orleans Saints face the San Francisco 49ers on Sunday, which quarterback they’ll go against — Alex Smith or Colin Kaepernick — is the least of their worries on that side of the ball.

Smith missed Monday’s game against the Chicago Bears because of a concussion, and his status for the matchup with the Saints is in question.

Kaepernick, a second-year pro, took over for Smith and directed the 49ers’ easy 32-7 win over the Bears, completing 16 of 23 passes for 243 yards with two touchdowns while posting a passer rating of 133.1.

Saints interim coach Joe Vitt was more concerned Wednesday with the 49ers’ top-ranked running game, which averages 165.3 yards a game and 5.5 yards per attempt.

“Both of those quarterbacks do a great job of functioning within the system, but this is a run-first offense,” Vitt emphasized. “They’re running the ball better than anybody in the NFL right now.

“They’re proficient at a gap scheme, they’re proficient at the toss-crack perimeter scheme, they’re proficient at pulling the guard to the front side. And they have a great wham scheme.”

Harbaugh coy

Niners coach Jim Harbaugh, who said Monday night he’ll go with the quarterback who has the hot hand if Smith is cleared to play, wasn’t about to let the Saints know who it’ll be.

“In both guys, we have quarterbacks we’re confident in and believe in — and have won for us,” he said, “Alex over a long period of 25 games and Colin playing winning football the last two times he’s been out on the field. Both have displayed that they are guys we believe in, are confident in, and can win for us.”

Vitt said the Saints just have to be ready for both and that they can’t be too consumed with who’ll start.

Strief returns

The Saints got good news Wednesday when tackle Zach Strief, who’s missed the past two games with a groin injury, was able to practice on a limited basis for the first time since being hurt on Nov. 5.

Strief said he had a procedure done by noted sports hernia specialist Dr. Williams Meyers, who repaired a core muscle injury and not a sports hernia.

Strief said Thursday will be a key day for him to see how he responds to Wednesday’s physical activity, but the decision to play or not play Sunday will lie with the coaches and trainers.

“I was just trying to get back into the routine and see how things are,” Strief said. “Right now, I feel great, but (Thursday) I could wake up and have swelling and not feel great.”

Practice report

Four Saints — defensive end Junior Galette (ankle), cornerback Corey White (knee), tackle Charles Brown (knee) and cornerback Elbert Mack (concussion) — did not participate in Wednesday’s practice.

Vitt said White, who missed last week’s game, is getting better quickly.

That could be a key because Mack, his replacement in the nickel package, has to go through the concussion protocol before returning to the field.

Roster moves

With Strief still not at full strength and Brown likely to miss Sunday’s game, the Saints signed tackle William Robinson to the active roster and released wide receiver Greg Camarillo.

Robinson, who will likely back up starter Bryce Harris, was on the Saints’ practice squad for 10 weeks in 2011 and was on the active roster for five games late in the season.

The Saints also brought in tackle Jermarcus Hardrick to fill a spot on the practice squad after guard Harland Gunn signed with the Atlanta Falcons.

Drew donates

Drew Brees and his Brees Dream Foundation are giving $1 million to help with the relief efforts from Hurricane Sandy in the New York and New Jersey areas.

“Obviously, we know the type of devastation a hurricane like that can cause,” Brees said. “We can only imagine the devastation and the way it’s changed people’s lives up there. I know they have a long road ahead of them.”