Montgomery left Wednesday's practice early with "what looked like a significant (leg) injury," Dan Wiederer of the Chicago Tribune reports.
Per Brad Biggs of the Chicago Tribune, Montgomery was carted off the field following a non-contact injury. The Bears will presumably send Montgomery in for further testing, after which a clearer diagnosis of his injury along with a potential timeline for his recovery will become available. Tarik Cohen should be in store for more reps with the first-team offense in the short term, but the Bears would more than likely add a veteran running back to the roster if Montgomery is forced to miss time.