Rookie Aaron Jones rushed 13 times for 49 yards and a touchdown after Montgomery and Williams both left with injury on Thursday night.
The key with Williams, though, is his health. Montgomery is "day to day" and could play in Week 5 with Green Bay on an extended layoff.
The Packers next play at Dallas on Sunday, Oct. 8.
The Green Bay Packers started the game with no healthy offensive tackles.
Montgomery wasn't the only Green Bay running back who got hurt on Thursday night.
Montgomery suffered the injury during the Packers' opening drive and was ruled out for the remainder of the contest. After all, the Packers are still going to throw the ball plenty with Aaron Rodgers under center, and Williams probably won't dominate the ball right away.
To make matters more complicated, running back Jamal Williams also left the game with a knee injury.
On that note, here are five running backs Packers general manager Ted Thompson could look to acquire.
While the fifth-round pick from UTEP doesn't scream season-shifting waiver-wire addition, the opportunity for regular work will be there if Williams is out along with Montgomery. He'll be relied on to keep Green Bay's offense balanced next week while the rest of their depth chart heals up.