Colorado led 2-0 early in the second period when O'Reilly was taken off the ice on a stretcher after losing his balance and slamming into the boards. A team official said O'Reilly had movement in his arms and legs and was taken to Regions Hospital. The injury delayed the game for about 10 minutes.
Kevin Porter, Milan Hejduk, Tomas Fleischmann and Ryan Wilson scored for Colorado.
Andrew Brunette scored for Minnesota.
Colorado extended its lead to 3-0 in the second when Fleischmann flicked a shot toward the net from the blue line and the puck bounced between rookie goalie Anton Khudobin's legs. Khudobin was playing because Niklas Backstrom and Jose Theodore, Minnesota's top two goalies, are out with lower-body injuries.
Once formidable at home, the Wild were booed by the hometown fans after the second period. They are 3-6-1 in their last 10 home games.
The Wild's lone goal came early in the third when Mikko Koivu's spin-o-rama pass from behind the net set up Brunette for an easy goal.
Colorado winger Chris Stewart played his first game since injuring his hand fighting the Wild's Kyle Brodziak on Nov. 27. Stewart was Colorado's leading scorer when he was injured.
Wild forward Cal Clutterbuck talked some trash after Minnesota beat the Avalanche on Dec. 23, leaving some to speculate that Colorado players could seek revenge on Friday.
There was a minor scuffle 27 seconds into the game, but no further incidents.
Porter and Hejduck scored in the first period. Wilson added an empty-netter late in the third.
NOTES: Wild coach Todd Richards didn't know if Theodore would be ready for Sunday's game against Vancouver. Backstrom skated in the morning and could be ready by Tuesday. ... The Wild recalled D Jared Spurgeon before the game and assigned F Patrick O'Sullivan to Houston of the AHL. The Wild also recalled Matt Hackett to back up Khudobin. ... The Avalanche placed winger Greg Mauldin on waivers to make room for Stewart. ... Hejduk's goal was Colorado's first in its last 29 power plays. ... Wild D Marco Scandella left the game in the third and didn't return after getting hit in the head with the puck.