Montgomery did not play in Saturday's preseason game against the Bills, Larry Mayer of the Bears' official site reports.
Montgomery overcame an undisclosed injury to return to practice earlier in the week, though the team decided to play it safe with its workhorse back. Damien Williams worked as the primary back in Montgomery's place and carried the ball five times for eight yards. It remains to be seen whether Montgomery will get touches in the team's final preseason game against Tennessee, though the focus presumably will be on him maintaining his health for the regular season.