The Avalanche are coming off a grueling 6-5 loss to the Tampa Bay Lightning. That's a heck of an effort against the best team in the NHL at the moment. The defense just wasn't able to contain the speed of Tampa.
The Avalanche defeated the Penguins back on December 11th by a score of 2-1. They came back the next night to lose to the Caps. Now they play the Lightning and Penguins back-to-back.

The Penguins are just 4-4-0 in December. Their win over the Coyotes stopped a three-game losing streak for them.
I think this is just a brutal stretch for the Avs in terms of their schedule. They took a hard 6-5 loss against the Lightning, and it'd seem they expelled a lot of energy into that game. Now they must turn around and play the Penguins. After taking a 2-1 loss to the Avs on the 11th, I see the Penguins responding in a big way on Monday night.