MacDonald was attempting to play the puck along the left boards in the Avalanche zone when he was hit by Lomberg. MacDonald appeared to land on his left arm as he fell backward.
No penalty was assessed on the play.
"Scary moment, but apparently he's seen our trainers and everything's good," Colorado coach Jared Bednar said after the 3-2 win. "I think [the hit] might have been clean, yeah. I only got the one angle on it. They kept showing it over and over, and it looks clean from there. Physicality's part of the game. I don't like seeing guys go down, especially when they can't get up, but I don't think you can take it out of the game."
The Avalanche provided an update during the second intermission saying that MacDonald was alert, responsive and had full movement, and that he was undergoing evaluation at Ball Arena.
"Just tough to see from probably either team," Avalanche defenseman Erik Johnson said. "It's a fast game out there, you move upwards of 20 mph. It's physical and things move fast. It's an unfortunate play, super scary for Jacob. It's tough, you just never want to see that and hopefully he's OK. I haven't heard anything yet. That's the stuff that makes you sick to your stomach when it happens to any teammate or opponent."
MacDonald has played in seven games for the Avalanche this season. He scored nine points (one goal, eight assists) in 33 games as a rookie last season.
NHL.com independent correspondent Rick Sadowski contributed to this report
