ENGLEWOOD, Colo. -- The Denver Broncos' backfield carousel shows no sign of slowing down.
Rookie Peyton Hillis, who had energized the Broncos offense over the last month, became the fifth Denver running back to go on injured reserve this season when medical tests showed he had a torn right hamstring behind the knee.
The Broncos now will turn to tailback Tatum Bell, who was selling cell phones at a Denver-area mall before he was re-signed last month. The team also will promote Cory Boyd from the practice squad to compete with P.J. Pope to serve as Bell's backup.
Broncos coach Mike Shanahan said Monday that Hillis will need eight weeks to recover from the injury, which might require surgery. Hillis was injured during the first half of Sunday's 24-17 win over the Chiefs when he planted his right leg and his knee locked while he made an acrobatic catch.
"It's always tough to lose a guy like that," Shanahan said. "But he will be good for the future. He's proved that he can play tailback in the National Football League, and that one catch he made was probably as good a catch as you could make in a very tough situation, and unfortunately, he pulled his hamstring making that catch."
Hillis had moved from fullback to tailback because of injuries to the Broncos' battered backfield, and he was the biggest surprise among the 12 rookies who received significant playing time in Denver this season.
Hillis rushed for 343 yards this season and scored five touchdowns, including an 18-yarder in Sunday's win that put Denver (8-5) on the brink of clinching a playoff berth. Hillis quickly emerged as a fan favorite by running over safeties and bullying his way past first-down markers and the goal line.
"It's disappointing you lose him at this time of year because he's a load and he's one of the few guys ever that I've watched that will actually run over safeties," Shanahan said of Hillis, a seventh-round draft pick who made his mark at Arkansas while blocking for first-round draft picks Darren McFadden (Oakland Raiders) and Felix Jones (Dallas Cowboys).
Hillis joins Broncos tailbacks Andre Hall, Michael Pittman, Anthony Alridge and Ryan Torain on the IR. Plus, Selvin Young, the Broncos' starter when the season began, has carried the ball just once in the last two months because of a torn groin.
Bell, the new starter, had a 28-yard run on Denver's winning 95-yard touchdown drive Sunday. He has rushed for 100 yards on 24 carries since his return to the Broncos, for whom he played from 2004 to 2006.
After a dismal 2007 season in Detroit, Bell was jettisoned by the Lions and went to work hawking cell phones and wireless plans at a kiosk at the Aurora Mall before the Broncos came calling last month.
"Well, when he has gotten his opportunity to play, he has played well," Shanahan said. "And he made a guy miss on that one sweep, and he did a nice job and got some big yards on that play. So, I've been pleased with him."
Taking advantage of his second chance, Bell has quickly adjusted to the Broncos offense. He rushed for 1,025 yards with Denver in 2006.
"I think anytime somebody's out on the streets for a while, everybody gets humbled," Shanahan said. "If a coach has been fired, a player that has been cut, it's the same thing. You look forward to those opportunities and you take advantage of those opportunities once you get them. And Tatum has come in, worked extremely hard, and he has taken advantage of an opportunity."
Copyright 2008 by The Associated Press.