Lions RB Zenner suffered partially collapsed lung

ALLEN PARK, Mich. -- Detroit Lions running back Zach Zenner has suffered multiple cracked ribs, a partially collapsed lung and is currently hospitalized.

Lions coach Jim Caldwell said he believes a procedure may be involved and that the rookie from South Dakota State will be placed on injured reserve.

"Things are improving for him," Caldwell said.

The rookie suffered the injury in the first half of Detroit's 37-34 win over Chicago on Sunday. He was initially taken to the sideline, where the doctors and trainers were examining his chest. He was taken to the locker room before halftime and did not return.

Caldwell said Zenner did not return home after the game, instead going to the hospital. He…