ENGLEWOOD, Colo. -- If there are indeed run-game gods, they are not smiling down on the Denver Broncos these days.
What was believed to be the one thing that would immediately work in the team's new offense has been something beyond a struggle. The Broncos are 31st in the league in rushing at 57 yards per game, are tied for last at 2.6 yards per carry and have had 21 rushing attempts this season (31.8 percent of their carries) go for no gain or negative yardage.
And now, just a handful of days before the Broncos face the Minnesota Vikings in Sports Authority Field at Mile High, injuries on the offensive line mean it continues to be a question mark.
"You can't put it in a nutshell," offensive coordinator Rick Dennison said of the Broncos' inability to consistently run the ball in the first three games. "There are a lot of little things. Certainly technique and assignments -- everything is involved in the run game. It's not anyone's fault. It's our entire team's problem, so we have to fix it together."
Yet fixing it "together" could involve additional, and unexpected, adjustments in the offensive front. Rookie left tackle Ty Sambrailo has been held out of two days of practice this week with a left shoulder injury he suffered in Sunday's win in Detroit, and left guard Evan Mathis was held out Thursday with a hamstring issue.
Mathis had tried to practice Wednesday, but the Broncos eventually pulled him out of that workout and then held him out Thursday.
"His hamstring was bothering him a little bit [Wednesday]," coach Gary Kubiak said. "He practiced. We pulled him out, so we held him [out] for rest and expect him to be back full-go [Friday]."
The Broncos also were concerned enough about Sambrailo's status to sign Tyler Polumbus Thursday. They will try to fast-track Polumbus through the playbook to get him ready to play, if needed, against the Vikings.
But Sambrailo was seen earlier this week with a sling on his injured shoulder, so the Broncos may need Polumbus ready to be, at minimum, the team's backup tackle against the Vikings. Polumbus has started games at left tackle, right tackle and left guard in his career.
"Fortunately, I've played a lot of football," Polumbus said. "X's and O's don't really change too much based on what team you go to. The terminology does. I've got to learn all the terminology, so I'll be swimming there. It will be a challenge for me to get caught up to speed."
It adds more uncertainty for a team with a struggling run game and that didn't play its starting offensive line together until the regular-season opener. The Broncos used the pistol formation more -- 29 times -- last Sunday against the Lions and that seemed to help upgrade the passing game; Peyton Manning finished with his first 300-yard effort of the season.
The Broncos are still searching for something to get the run game going as well.
"We're just going through some of the pains of an NFL season and how you adjust to them, how you find a way to play through them, it says a lot about who you are," Kubiak said. "We're having to do that right now. Hopefully we get everybody back quick."