GREEN BAY -- Packers Head Coach Mike McCarthy said Friday morning that he does not expect RB Ty Montgomery to play Sunday vs. Baltimore.

Montgomery is on the injury report with a rib injury, the second time this season he has dealt with his ribs. He had been playing with a flak jacket underneath his jersey but had to leave last week's game at Chicago late in the first half, in which he ran for a 37-yard touchdown. He did not practice Wednesday or Thursday.

"I think Ty is going to be out this week," McCarthy said. "I don't think there's a long-term concern."

With Aaron Jones (knee) also out, that turns over the backfield to rookies Jamaal Williams and Devante Mays. Williams rushed 20 times for 67 yards in the second half against the Bears last week. Mays has been active on game day only three times this season and has yet to take a snap on offense, playing only special teams so far. WR Randall Cobb and FB Aaron Ripkowski also remain options in the backfield.

As QB Brett Hundley strives for his first home win as a starter, he'll be playing in his first true cold-weather game as a pro. Temperatures are expected to be in the low 30s on Sunday in Green Bay, and there could be some chilly winds thrown in as well.

McCarthy said the grip on the ball is the most important thing for a quarterback transitioning to a cold-weather game. Hundley, a native of Arizona and alum at UCLA, played in a few cold games in college, but not many.

"You have to be in tune with the rest of the things around you, but when you get to this time of year, obviously the ball doesn't travel as far," McCarthy said. "Really, handling the football is the focus."