Lee will undergo an MRI on his neck Tuesday in Dallas.
Lee was hurt with 12:33 left in the quarter but returned for five plays before he was sent to the locker room.
Lee missed the Cowboys' previous two games with a hamstring injury suffered on Nov. 10 against the New Orleans Saints. He was able to make it through a week of practice and returned to his inside linebacker spot against the Bears.
Lee has yet to play a full season. He missed two games as a rookie with a hamstring injury, one game in 2011 with a dislocated wrist and 10 games last year because of a toe injury that required surgery. The Cowboys signed Lee to a six-year extension in the offseason worth $42 million with a $10 million signing bonus. Some of the money in the future was tied to Lee's playing time in 2013-14.
The Cowboys also lost weakside linebacker Bruce Carter to a hamstring injury on the same drive they lost Lee. Wide receiver Dwayne Harris injured a hamstring on a 43-yard kickoff in the third quarter. He was returning after a one-game absence due to a hamstring injury.