Ryan Williams and NFC West's future RBs

GLENDALE, Ariz. -- Issues with Ryan Williams' surgically repaired right knee sent the Arizona Cardinals' third-year running back to the sideline less than three full practices into the team's first training camp under coach Bruce Arians. An MRI exam showed no new damage, Arians said Monday, but Williams will seek a second opinion just to be sure. No one is quite sure when the 2011 second-round draft choice might be cleared for return.

The occasion provides an opportunity to examine as a group Williams and the other prominent halfbacks NFC West teams selected in 2011 and 2012. None was selected to start immediately, so we shouldn't evaluate them solely on production. This sixsome has endured a torn Achilles' tendon (Kendall Hunter), a torn patella tendon (Williams) and a one-game suspension (Isaiah Pead). All will likely serve as backups or in committees.

Williams, who has sometimes appeared dynamic on the practice field for his ability to change direction without losing much speed, could face a make-or-break season after knee (2011) and shoulder (2012) injuries kept him off the field. "I would think so," Arians said.

NFC West teams continued drafting running backs in 2013. They selected a league-high six of them: second-rounder Christine Michael (Seattle), fourth-rounder Marcus Lattimore (San Francisco), fifth-rounder Zac Stacy (St. Louis), fifth-rounder Stepfan Taylor (Arizona), sixth-rounder Spencer Ware (Seattle) and sixth-rounder Andre Ellington (Arizona). Ware has played some fullback in the past and is playing that position now.

The division parted with two incumbent starters when Arizona released Beanie Wells and St. Louis let Steven Jackson out of his contract. The Seahawks' Marshawn Lynch and the 49ers' Frank Gore appear likely to produce at high levels again this season, but their teams are increasingly in position for the future.

Halfbacks NFC West Teams Drafted, 2011-2012