Barber gingerly walked off the field after 35-yard run in the fourth quarter of the Cowboys' 33-31 loss Sunday night in the home opener against the New York Giants.
Coach Wade Phillips says Barber had an MRI on Monday. He says the Cowboys will have to wait to "see where we are" on Barber.
Barber ran for 124 yards and a 2-yard touchdown in the loss.
The Cowboys host Carolina next Monday.