The Arizona Cardinals placed rookie first-round draft choice Jonathan Cooper on the season-ending injured reserve list Friday after determining his broken leg would need a full season to heal properly.
Cooper, chosen seventh overall, was the Cardinals' starting left guard and the centerpiece of an evolving line.
"Based on the medical prognosis and weighing all of the other factors, we decided that placing him on IR made the most sense for the team and for Jonathan," first-year Cardinals general manager Steve Keim said in a statement released by the team. "Knowing his work ethic and commitment, we have no doubt Jonathan will come out of this experience fully ready to be a key contributor next season and for many more beyond that."
Cooper suffered the injury while making a block 9 yards downfield after pulling around the formation during a preseason game against the San Diego Chargers. The play showcased the athletic ability Arizona coveted when Keim, himself a former guard at North Carolina State, made Cooper the first offensive lineman the Cardinals had taken in the first three rounds since 2007.
Arizona and the Tennessee Titans were the only teams not to select an offensive lineman in the first three rounds from 2008 through 2012.
Veteran Daryn Colledge moved from right guard into Cooper's spot. Colledge was the starting left guard last season. The Cardinals have better depth on their offensive line this season, but losing Cooper is a significant blow. This marks the second year in a row Arizona has lost a highly drafted offensive lineman to a season-ending injury in preseason. Left tackle Levi Brown, chosen fifth overall in 2007, went on injured reserve about this time last season.
Arizona surrendered a season-high 58 sacks last season, but only 19 in its final eight games. New quarterback Carson Palmer ranks tied for ninth in lowest sack rate over the past two seasons. Arizona will rely upon Palmer's quick decision-making to reduce sacks, even as the team shifts to an offense emphasizing deeper pass routes requiring longer time for receivers to get open.
The team released 13 players, including wide receiver Mike Thomas and defensive tackle David Carter.
Others released are safety Jonathan Amaya, center Adam Bice, wide receiver Dan Buckner, tight end Alex Gottlieb, wide receiver Charles Hawkins, guard Senio Kelemente, linebacker Zack Nash, linebacker Colin Parker, tight end Richard Quinn, guard Chilo Rachal and safety Curtis Taylor.
Information from The Associated Press was used in this report.