Both were activated before the team's game Friday night against the Vancouver Canucks.
Galiardi has missed nine games since injuring his ankle Oct. 28 at Calgary. He has one goal and five assists for Colorado this season.
Liles missed five games after injuring his shoulder Nov. 6 against Chicago. He has two goals and three assists for the Avalanche this season.
The Avalanche also reassigned forward Chris Durno to the Lake Erie Monsters of the American Hockey League on Friday and placed forward Matt Hendricks on the injured reserve list retroactive to Nov. 14 with a groin injury.
I downplayed the first one because I thought it's just a hockey game. We just want to win the game; it's against our rival and we want the two points. I downplayed it, but now having gone through the first one I look back and say, 'Geez, that was really cool.' I think as I've grown a bit older I've got a lot more appreciation for what we're allowed to do every day.
— Capitals forward Brooks Laich on the 2015 Bridgestone NHL Winter Classic, the second one of his career after 2011 in Pittsburgh