Mike Bell nervously walked into Mike Shanahan's office late Sunday night and expected to hear bad news from the Denver Broncos coach.

"I was shaking," Bell recalled Monday.

The undrafted rookie was then told that he leapfrogged veterans Tatum Bell and Ron Dayne to claim the No. 1 running back spot. Bell becomes the latest to assume a job that has routinely produced 1,000-yard rushers during the last 10 years.

"This is a dream come true," the former Arizona star said. "For him to give me the opportunity to be the starter on a great organization like this is a blessing."

It wasn't the only big piece of news out of Broncos camp, rookie Jay Cutler was promoted to backup quarterback, replacing Bradlee Van Pelt behind starter Jake Plummer.

Bell's leap to the top of the depth chart is even quicker than that of former Denver running back Terrell Davis, who came into camp as a sixth-round draft pick in 1995 and won the starting job by the first week of the season.

Bell, who grew up idolizing Davis, earned the job — at least for now — before playing a single down.

"He's been real impressive," Shanahan said.

Bell entered camp as the fourth-string running back, but quickly impressed the coaching staff when they went back and analyzed film from training camp.

Dayne saw the elevation of Bell coming days ago based on his performance at practice.

"Mike has been out here killing practices," Dayne said.

Terrell Owens sat out a sixth straight practice because of soreness in his left hamstring that set in last Wednesday. It will likely land him on the bench for the Cowboys' preseason opener in Seattle.An MRI exam over the weekend showed no damage, but that didn't seem to matter to Owens when he was asked whether he would play against the Seahawks on Saturday."I doubt it," he replied.Owens, who signed with Dallas in the offseason, probably won't practice the rest of this week. Hoping to speed things up, the star receiver is shipping his healing-inducing hyperbaric chamber to his training camp hotel room. Owens' personal medical staff is on its way from Atlanta.