Cardinals RB Ryan Williams said he was "scared all last year to get the ball in my hands."

Williams was coming off a torn patella tendon sustained during the 2011 preseason. "It was something where I was trying to protect my leg instead of trying to protect the football," he admitted. "It's a scary sight being a running back and being scared to run the ball. That's something that no running back should feel." Williams averaged a pathetic 2.82 YPC before sustaining a season-ending shoulder injury in Week 5. He says the fear is now gone, but he'll have to prove it with the pads on in order to earn carries in Arizona. Rashard Mendenhall, Stepfan Taylor and Andre Ellington are all in the mix as well.

Coach Bruce Arians reiterated that the running back spot is open to competition.

Rashard Mendenhall may be the slight favorite as he had his best years under Arians in Pittsburgh and will be roughly 20 months removed from his ACL tear when Week 1 rolls around. But Ryan Williams, Stepfan Taylor and Andre Ellington will all be in the mix as well. "You really can't tell until the lights come on," Arians said. "Some were different from this morning's walkthrough to the afternoon practice. Until you turn the lights on, you really don't know about them."

New coach Bruce Arians said he prefers not to use a running back by committee approach.

"Backs by committee, one of them gets hurt you've lost half your committee or a third of your committee," Arians said. "I like guys who can play every down." Ryan Williams is the logical candidate to fill the gig, but he'll have to prove his ever-questionable health. The Cardinals are also a good bet to add talent to the position via free agency or the draft. They've been linked to the likes of Rashard Mendenhall and Reggie Bush, among others.

Cardinals GM Steve Keim says the club is "expecting big things" from third-year RB Ryan Williams.

Williams has been injured since his redshirt freshman year at Virginia Tech, but the Cards aren't giving up. "We watched him against Philadelphia ... (and) New England," Keim said of Williams' 2012 tape. "His lateral quickness, his natural run skills, his avoidability is something he brings to the table. Plus he's a three-down back. We're expecting big things out of Ryan moving forward."

Ryan Williams (shoulder) admits he's worried about his roster spot.

"Who wouldn't (be)?," Williams said. Injuries have limited Williams to just five games in two years since being the No. 38 pick of the 2011 draft. However, Williams says he's the "happiest I've been in two years," and that he's "gotten right" both physically and mentally. New coach Bruce Arians is an avowed Williams fan. "I know Ryan can flat run the football," Arians said. "I know all about Ryan, and I love him." Williams is expected to be 100 percent for the Cardinals' offseason program.

New Cardinals coach Bruce Arians said Friday that he "loves" Ryan Williams and "lit up" when discussing the 2011 second-round pick.

Arians and Williams both went to Virginia Tech, and it sounds like Arians is smitten with Williams' ability. The 38th overall pick in the 2011 draft, Williams' first two seasons in the league were derailed by major knee and shoulder injuries. He's still only 23 (in April) years old, however, and Arians had success with far less talented Vick Ballard with the Colts in 2012.

Cardinals RB Ryan Williams (IR, shoulder) said Wednesday he now feels the best he has in the last two years.

Ryan Williams admitted that his knee was still a major concern before suffering a season-ending shoulder injury in Week 5.

Ryan Williams will require surgery on his left shoulder and is done for the remainder of the season.

It's a rough blow for increasingly one of the league's most tough-luck players. Williams suffered the injury in last Thursday night's loss to the Rams. William Powell figures to be the favorite for carries in Arizona's backfield until Beanie Wells (turf toe) gets back in Week 12 or 13, although Powell is coming off a "head" injury. La'Rod Stephens-Howling and Alfonso Smith will also be in the mix for carries behind an offensive line that opens no holes. Williams will enter the 2013 season having not been a legitimately productive rusher since 2009, his redshirt freshman season at Virginia Tech. After also missing all of 2011 with a ruptured patellar tendon, Williams' long-term outlook is all sorts of cloudy.

Cardinals RB Ryan Williams played 43-of-82 (52.4 percent) snaps versus the Rams in Week 5.

Even with the shoulder injury that knocked him out of the game, it's an increase from last week. Williams even saw time in the no-huddle package. Backup William Powell played just 12 snaps Thursday night. Williams now has just one impressive quarter in 20 this season, but he's locked in as the feature back as long as his shoulder checks out on Friday.