"We don't have a clear answer exactly on what Ty is dealing with and how we move forward," McCarthy said. "The conversation he's had with the trainers, he's preparing to play in Dallas [in Week 5].
"That's what this weekend is for. On Tuesday we'll get our hands around it and get all the information."
Montgomery was used heavily before he exited, picking up 28 yards on five runs on the opening drive's first six plays. Rapoport reported that Montgomery suffered the injury early in the drive and played through it briefly.
Wide receiver Davante Adams left the field on stretcher and was transported by ambulance to a nearby hospital after taking a helmet-to-helmet hit from Bears linebacker Danny Trevathan, who was given a personal foul on the third-quarter play. Adams was being evaluated for head and neck injuries and a possible concussion, the team reported. He was conscious and had movement in his extremities, according to the team.
Packers backup back Jamaal Williams was also ruled out after suffering a knee injury in the second quarter. Williams received the bulk of the carries in Montgomery's absence, picking up 11 yards on four carries. Williams was the only other Green Bay running back to carry the ball in 2017 until rookie Aaron Jones filled in for him in the second quarter.