"Here we go again on the search for backup help to Steven Jackson in the Rams' backfield. The free-agent additions of Cadillac Williams and Jerious Norwood looked good on paper last summer at the start of training camp.

But Williams was so-so, with some notable problems on swing passes early in the season. Norwood barely played. Both are free agents this offseason and aren't expected back.

As usual there were plenty of potential running back options on display this week at the Senior Bowl, with the headliners being Chris Polk of Washington and Doug Martin of Boise State. Both project as second- or third-round draft picks.

There are few backs in the country, or in the history of the Pacific 12 Conference, as productive as Polk with the Huskies. He posted back-to-back seasons of 1,400-plus yards rushing, and with 4,049 career rushing yards is only the seventh rusher in Pac-12 history to top 4,000.

At 5-10½ and 224 pounds, Polk is a strong physical inside runner. He's not going to make you miss, but he will run through arm tackles and rarely gets caught in the backfield for a loss.

"He's so strong in the lower body," said one veteran AFC scout. "He gets a lot of yardage after contact. He breaks tackles with his legs because he's strong."

Polk is an erect runner, meaning he takes a lot of hits. And some scouts question his speed, to which Polk takes offense.

"I've been fast my whole life," Polk said. "It's just a matter of showing it. I think they think I'm slow because of my running style. I'm real patient. If I see a crease, I'm gonna hit it 100 mile per hour.""