And to add a little more insight to this thread....
From the DenverPost..
Since Shanahan took over as head coach in 1995, the Broncos' system has cranked out 20,150 rushing yards during the regular season. That's the most by any NFL team from 1995-2003. The succession of quality backs included Davis, Olandis Gary, Mike Anderson and Portis. Each rushed for more than 1,000 yards in his rookie season.
But just as the Broncos are searching for a go-to wide receiver, they also are searching for a big-play running back. At minicamp, Quentin Griffin was running with the first team. The former Oklahoma Sooner rushed for 136 yards in a regular-season victory at Indianapolis last season, and Shanahan likes Griffin's quickness and work ethic. But questions remain about whether a 5-foot-7, 195-pound player can be a featured back in the NFL.
There also are questions about rookie Tatum Bell, this year's second-round draft choice from Oklahoma State. Although Bell's 4.26-second 40-yard dash made him the fastest back in the 2004 draft, he must prove he's tough enough to grind out yards between the tackles.
"I think Tatum will be a lot more productive now than he would have been two years ago," Oklahoma State offensive coordinator Mike Gundy said. "Two years ago, he would not have been tough enough, mentally or physically. But he's come a long way since then. We put a lot of pressure on him and he responded. He grew up."
Gundy predicted the Broncos will reap benefits from Bell this season - after a few growing pains.
"If I were a betting man, I'd say by the fifth or sixth game of the season, he's going to help that team win some games," Gundy said.
No mention of Hearst as he's still nursing his injury.