Allen was not flagged on the play, though Louis left the game immediately after with a knee injury.
When asked about it afterward, Allen said, "I never, ever try to intentionally hurt anybody. Just trying to make a block and spring our guys down the sidelines. That's unfortunate."
Allen has been in trouble with the league -- he was fined $7,500 earlier this season for a scuffle with Tampa Bay's Donald Penn.
This hit, however, could be a tough one for the NFL.
Was it helmet-to-helmet? Allen definitely launched himself into Louis, but the hit came from in front of the Bears' lineman, who was chasing down the play.
Will Allen's past transgressions play into a decision? He was suspended in 2007 for violating the league's substance-abuse policy, fined $50,000 in 2008 for a low hit on Matt Schaub and $25,000 earlier that season for a hit on Aaron Rodgers. However, Baltimore's Ed Reed had a suspension overturned this week after he was initially hit with a one-game punishment for repeated illegal hits dating back three seasons. The Vikings, now 6-5 on the season, travel to Green Bay next week.