The Saints will rely on gimpy Zach Strief (above) or rookie Bryce Harris to stop the 49ers DE Aldon Smith. (US Presswire)

The streaking Saints could be down to their third right tackle when they face the 49ers and dominating defensive end Aldon Smith on Sunday.

Normal starter Zach Strief, who has missed the last two games with a groin injury, returned to practice on a limited basis Wednesday but said he was not sure he would be ready to play. His backup, Charles Brown, is definitely out after hurting his knee against Oakland last Sunday.

That leaves either a gimpy Strief or undrafted rookie Bryce Harris to face Smith, who has an NFL-record 28.5 sacks in his first 26 games and usually lines up against the right tackle.

“They have outstanding pass rushers,” Saints interim coach Joe Vitt said. “They have great edge pressure, they have strong people in the middle. Our ability to create a firm pocket for Drew [Brees] is going to be critical.”

The real test for Strief will come Thursday and Friday in practice.

“I’m happy that it feels as good as it does,” Strief said. “I’m ahead of schedule, but we’ll see how it responds after a day of work. I felt good today, but at the same time, you have to wait and see how it responds.”

The Saints signed Harris off the Falcons’ practice squad in early September. He was inactive for the first eight games and did not play before Brown went down in the last two minutes of the first half Sunday.

“He jumped in there last week without a lot of reps and played with some poise,” Vitt said. “It really helps him that he’s playing next to Jahri (Evans). Jahri’s a good communicator.”

Vitt said the Saints picked up Harris because they liked his athletic ability, his footwork and his base. They weren’t expecting him to play, though, and if Strief performs well in practice, he won’t have to against the 49ers.

Brees threw 63 passes in New Orleans' divisional playoff loss to San Francisco last year and was sacked three times. Smith had 5 ½ sacks alone against Chicago this Monday night.

Follow Saints reporter Guerry Smith on Twitter @CBSSaints.