Nielsen was placed on waivers by the Avalanche on Sunday.
Nielsen had a chance to factor in for the Avs to begin the upcoming campaign, but the team elected to move forward with Georgi Merkulov and Parker Kelly to battle for an everyday depth center role. The 26-year-old Nielsen had a solid tryout at the NHL level last season, where he posted an assist, three shots on net and nine hits across four regular-season games. He was effective in his first full season with AHL Colorado, posting 49 points across 66 regular-season outings, which should allow him to retain a large role with them to open the upcoming campaign.