The Arizona Cardinals made it official on Tuesday and placed running back Ryan Williams on injured reserve because of a shoulder injury.
Williams was hurt during Thursday's game against St. Louis and Cardinals coach Ken Whisenhunt on Monday said the second-year back out of Virginia Tech would miss the remainder of the season.
A ruptured patellar tendon in his right knee kept Williams sidelined for his entire rookie season after the Cardinals selected him in the second round of the 2011 draft.
The 22-year-old ran for 164 yards on 58 carries and caught seven passes for 44 yards this season.
Arizona re-signed cornerback Crezdon Butler to fill the vacant roster spot. Butler was among the team's final cuts in August, then played two games with the Washington Redskins before being released in late September.
Butler played in one game for the Cardinals last season before an ankle injury ended his campaign in September.