Keeping an eye on Cardinals' Ryan Williams

FLAGSTAFF, Ariz. -- The Arizona Cardinals' decision to draft a running back in the second round came as a surprise.

The team wasn't hurting for prospects at the position.

One week into training camp, it's easier to see why the Cardinals made Virginia Tech's Ryan Williams the 38th player drafted this year.

Williams is wearing No. 34, but no one should confuse him for Tim Hightower, who wore the number last season. Williams' quickness and ability to change directions fluidly while moving at a fast clip separates him from Hightower and 2009 first-round choice Beanie Wells.

Wells opened training camp as the No. 1 running back. That has not changed.

Wells opened Arizona Cardinals training camp as the No. 1 running back. Watching Williams run and knowing Wells' injury history raises questions in my mind about which player will be the primary back by season's end.

"I am a very instinctive runner," Williams said Friday. "If I feel it, I’ll do it. If it’s a cut and I’m running 100 miles an hour, I make that cut at 100 miles an hour."

Wells' margin for error was not great when Hightower was on the roster. It's no greater without him. Both Wells and Williams rank high on my list of players to watch during the exhibition season.