The Arizona Cardinals have placed running back Ryan Williams on injured reserve, officially ending his season. The team surprised many by filling his roster spot not with a running back, but by bringing in cornerback Crezdon Butler, recently released by the Redskins.

Butler was drafted by the Pittsburgh Steelers in 2010, and claimed off waivers by the Cardinals soon after. He was waived by the team during final cuts this preseason, and spent two games with the Washington Redskins, before being waived injured.

With such obvious lack of depth at running back, and with former Cardinals running back Tim Hightower currently a free agent, many were surprised by the move. The Cardinals secondary has been relatively solid throughout the course of the season, and already have depth at the position, making the decision even more confusing.

The Cardinals could, of course, still add a running back through free agency or trading—Hightower, for example, is still considered around two weeks away from full fitness—and Butler could purely be a stop gap measure or coverage for some unreported injury. However, there is another option which many appear not to have considered—Patrick Peterson playing on offense.

The Cardinals have practiced extensively with Peterson as a running back, in the wildcat formation and as a receiver, and have spoken of their desire to use him more extensively in this roll. However, as their primary cornerback and punt returner, Peterson already spends more time on field than almost any other player. Using him offensively on more than a half a dozen trick plays per season has proved nearly impossible.

Butler is not an every down cornerback, and is unlikely to beat out any of the Cardinals current players—Peterson, Greg Toler, William Gay, Michael Adams or even rookie Jamell Fleming—for a regular starting job.

But by adding still more depth to this position, the Cardinals can, conceivably, sit Peterson out of a few more defensive plays, allowing him to take a more regular and active role on offense.

Peterson is well known for his elusiveness in the open field, returning four punts for touchdowns last season, and could really add a level of dynamism to the Cardinals offense, either out of the wildcat, lining up as a traditional running back or catching screen passes. Furthermore, his vastly improved tackling in 2012 when compared to his rookie year would conceivably allow him to become involved in pass protection too.

The risk of injury and his importance on defense must not be underestimated, and this would always limit the number of touches a player like Peterson would receive in a game. But even giving number 21 just two or three touches a game could really see the Cardinals running game come to life.

The Cardinals have really struggled moving the ball up the middle, in no small part due to the weakness of their offensive line, but Peterson, and running back LaRod Stephens-Howling are both quick and elusive players, very difficult to catch and tackle in open field. If the Cardinals can establish a running game to the outside, even on a limited number of touches, this would really open up the middle of the field for players like William Powell and Alfonso Smith, as well as taking pressure off Kevin Kolb.

While it would be inconceivable to expect Peterson to move to the offense on anything more than an occasional basis—he is quickly establishing his reputation as one of the best upcoming shutdown corners in the NFL—including him on offense even infrequently may just give the Cardinals ground game the boost it needs. And with no shortage of young but talented runners desperate to establish themselves in the absence of Williams and Beanie Wells, a small boost is likely all that it would need.