Detroit — Lions running back Zach Zenner exited with a chest injury in the second quarter of Sunday’s game against the Bears and will not return, the team announced before the start of the second half.

Zenner suffered the injury on a hard hit by Chicago safety Adrian Amos after a 7-yard run. After trainers examined him on the sideline, Zenner walked to the Lions locker room on his own power.

Without Zenner, the Lions have just two healthy running backs, Ameer Abdullah and Theo Riddick. Veteran Joique Bell (ankle) was inactive.

Before the injury, Zenner had three carries for 15 yards. The Lions finished the first half with 82 rushing yards, already surpassing their season high of 69 yards from Week 1.

In addition to losing Zenner, defensive end Jason Jones left late in the second quarter and is out.

At halftime, the Lions led 21-13.