The Detroit Lions have lost their top running back for the foreseeable future. Ameer Abdullah is heading to injured reserve after injuring his left foot during the second quarter of Sunday's 16-15 loss to the Tennessee Titans.

Lions coach Jim Caldwell said Wednesday that Abdullah underwent foot surgery, but he wouldn't go into details on the procedure. When asked whether Abdullah could return this season, Caldwell said, "We'll see."

It is possible Abdullah could return later this season, as each NFL team can bring one player back off injured reserve.

Abdullah injured the foot on a 24-yard run in which he broke multiple tackles. At the end of the run, he hobbled off the field and went almost directly into the team's locker room. He did not return.

Initial X-rays on the foot showed no broken bones, a source said, but Abdullah went to Charlotte on Tuesday for a second opinion with specialist Dr. Robert Anderson. On Wednesday, the Lions placed him on injured reserve.

Abdullah was Detroit's No. 1 running back, gaining 101 yards on 18 carries this season. He also caught 5 passes for 57 yards and 1 touchdown.

"Guys have got to step up and play," Caldwell said. "Somebody has got to take a few more carries than they would have ordinarily, and obviously I think we have a number of guys we can do that for us."

Lions RB Ameer Abdullah rushed for 101 yards on 18 carries before going on IR with a foot injury. Scott W. Grau/Icon Sportswire

With Abdullah out, Theo Riddick becomes Detroit's top running back, with rookie Dwayne Washington and second-year pro Zach Zenner also having roles. The Lions worked out one of their former running backs, Joique Bell, on Tuesday, according to ESPN Insider Adam Caplan, but Bell has not signed with the club.

Detroit signed wide receiver Aaron Dobson to take Abdullah's place on the roster. The Lions also signed linebacker Zaviar Gooden and running back George Winn to the practice squad and released guard Chase Farris and wide receiver Isaac Fruechte. Linebacker and running back are two positions of need right now for the Lions due to injuries.

The Lions are dealing with a lot of injuries. Among the players missing from Wednesday's practice: Defensive linemen Ezekiel Ansah (ankle), Tyrunn Walker and Wallace Gilberry; linebackers DeAndre Levy (quad), Kyle Van Noy (calf) and Antwione Williams (thigh), tight end Eric Ebron and starting right tackle Riley Reiff.