The Packers came away with a huge 37-36 victory, and the numbers for Lacy were impressive. He finished with 141 rushing yards and a touchdown on the ground along with another 30 receiving yards, giving him 23 fantasy points in ESPN's standard scoring leagues.
Heading into this week, he had already run for 887 yards and seven touchdowns, with another 206 receiving yards. He's consistently had solid games this year, while his only bad recent fantasy performance came on Thanksgiving against the Detroit Lions.
While Lacy has been good, there's a chance that he will struggle for the last two weeks of the season. He can hit the holes and make big plays, but stamina could be an issue with games remaining in Green Bay and Chicago. The rookie running back had to leave a game a few weeks ago because of issues with asthma, which could flare up again in cold weather.
Plenty of owners will still probably start Lacy, and that's fair. But personally, I would be wary about him if he isn't able to get a big workload for the final two weeks. I have him as a flex player at best.