Taylor Martinez is still sidelined with a turf toe injury, causing Husker coach Bo Pelini to categorize the senior quarterback as "doubtful" for Saturday's game.

It likely means a freshman will be starting at quarterback for the Huskers when they take on South Dakota State.

"If we were to (play) today, we'd probably start with Tommy Armstrong," Pelini said after Thursday's practice. "But you'll see Ronnie Kellogg. We want to make sure we look at this practice film. I haven't visited with Tim (Beck) since practice was over, but that's kind of the way we were leaning going into today."

It would mark the first time in 32 games — Colorado in 2010 — that Martinez did not take the field as Nebraska's starting quarterback. He has missed just two games at the position since winning the job as a freshman.

If Martinez isn't ready to start, Pelini said he didn't think coaches would suit him up as an emergency backup plan.

"I want him to be 100 percent, and I have full confidence in those two other quarterbacks," Pelini said.

Armstrong, meanwhile, has put himself in position to be the next option by turning up his game the past couple of weeks.

The redshirt freshman was slowed at the beginning of fall camp after having his knee cleaned out. But the 6-foot-1, 220-pound native of Cibolo, Texas, has started to find his rhythm of late.

"He was struggling a little bit. He was a little frustrated from the time he missed and also how he was feeling," Pelini said. "But he's made a big jump. He had a tremendous week of practice, and they both practiced well. It's very close as far as that's concerned. Like I said, I have confidence in both guys."

While some might make the argument that Armstrong is the right call this week since he represents the future at the position, Pelini said, "We're just worried about what's best for our football team this week."

The veterans Martinez and Kellogg have done a great job of helping Armstrong learn his way, the coach said.

"That happens across the board on this team. Young, veteran, whatever. Guys work together and push each other. That's what it's all about."

Armstrong dipped his toes in the water in the Southern Mississippi game, coming into the game in the fourth quarter of a 49-13 game and directing the team on a nine-play, 64-yard drive.

The quarterback has still yet to throw a pass in a collegiate game, but he showed off his option skills, carrying the ball four times for 23 yards.

"I was real nervous, but after that first snap, I just got into the way I always used to play," Armstrong said that night. "It just felt right."

Reach Brian Christopherson at bchristopherson@journalstar.com or 402-473-7439. Follow him on Twitter @HuskerExtraBC.