Thomas averaged 3.3 yards on 14 carries for a total of 46 yards.
The Bears' paltry 140 net yards of offense came against the 30th-ranked defense.
"We really haven't been able to run the ball, and, of course, we haven't got much out of the passing game," Lovie Smith said.
Bears guard/tackle Steve Edwards said the absence of a passing attack has made it almost impossible to block in the run game.
"Teams are going to bring it," he said. "They're going to jam the front, stack eight in the box, do whatever they've got to do to stop the run because they know they've to do that. We've got to pass to help the run out."
A plea for help?
CEL-A-BRATE GOOD TIMES
The worst third-down offense in the NFL could celebrate Thursday. They were better than Dallas at converting third downs.
The Bears converted 2-of-14 while the Cowboys converted 1-of-13 -- not much to cheer about.
"We just weren't converting on third downs, which has been a problem all year," Bears quarterback Jonathan Quinn said. "And there were some miscommunications (in the passing game)."
The Bears also had three failed third-and-ones -- an area which had been a strength.
Tillman didn't get credit for a tackle or pass breakup in his return to his home state.
"I don't know if I'm going to start next week or what," Tillman said. "Coach (Vance) Bedford is interchanging us."
Tillman had one problem after eight weeks away.
"Just the wind. Just trying to get my wind back," he said.
READY, WILLING AND ...
Quarterback Chad Hutchinson said he'll be ready if called upon against Minnesota next week.
"I'm eager to play whenever I step on the field," he said. "It would be nice -- whatever role they're going to give me, I'll take.
"It's one of those things that's out of my control."