For someone who's never carried the ball in a regular season game, the Seattle Seahawks are sure enamored with running back Louis Rankin.

To the point where the NFL's active rushing leader, Edgerrin James, was sent away earlier this week to see if Rankin could provide a missing jolt for Seattle's struggling run game.

"What Louis adds is the element of speed. That man is extremely fast and shifty," Seattle coach Jim Mora said. "And on a daily basis we watch him go out there and give our defense a real test. And so we want to see that."

No one is quite sure just how much Rankin will be used on Sunday when the slumping Seahawks host Detroit. About the only guarantee is it seems obvious the guy cut from the Oakland Raiders earlier this season likely will get his first NFL carry taking over the role held by James before his release.

James was used in a spot role to spell starter Julius Jones, but couldn't provide the spark Seattle wanted. That was due in part to a makeshift offensive line that's been significant in Seattle's problems running the ball.

Since being signed by the Seahawks, Rankin has caused headaches for Seattle's No. 1 defense as a scout team back. His natural speed is a change-up the Seahawks hope can help boost a run game averaging just 89 yards per game.

"We do like what Louis adds and we're anxious to see it in a game so we want to get him some touches," Mora said.

The fact that Rankin is at this point of being the guy Seattle thinks can be a help caps a rapid rise. Coming out of Washington, Rankin heard rumors he might get drafted only to get bypassed by everyone in the 2008 draft.

Then the phone didn't ring. His agents had to make the calls to see if anyone might take a chance on a lanky back who ran for 1,294 yards his senior season at Washington, including the fourth-best performance in school history when he rushed for 255 yards against Stanford.

Eventually, the Raiders signed Rankin to their practice squad and he was on the active roster at the end of the 2008 season. But Rankin said he felt pigeonholed into a specific role with Oakland no matter what he showed on the field.

"I don't think they expected me to do as much as I did. In Oakland they already had my role picked out no matter. I told the coach, 'if I went out and scored every play you guys would still have me in the same position you do right now.' He didn't disagree with it," Rankin said. "Going in there that was something I dreaded ... but I think I got what I needed to get out of Oakland and things are working out right now."

There's very little for Seattle to go on in determining how effective Rankin will be. All his carries as a professional have come during the preseason, with his best game being his first - nine carries for 91 yards against San Francisco in the first exhibition game of 2008. Included in that total was a 72-yard run.

This season, while still with Oakland, Rankin rushed for 60 yards on six carries and a 45-yard touchdown in the preseason finale against the Seahawks. The potential for breaking a long run of 30 or more yards, something Seattle has done only once this season, is what the Seahawks hope Rankin can bring.

"I just try and go out there every day and not take any plays off. Every play I try and give my best and that's something that's easily noticed," Rankin said. "People notice quickly that I'm not taking any plays off and I'm going full speed. Whenever you do that, something good is going to happen."