Middleton was placed on waivers by the Avalanche on Sunday.
Middleton faced an uphill battle to make the Avs' roster out of training camp, with the team returning the majority of its defensive core from last season. The 28-year-old blueliner had a solid NHL showing in limited action during the 2025-26 campaign, where he posted an assist, four PIM and six hits across three regular-season outings. He's set to open the upcoming campaign with AHL Colorado, marking his seventh season with the Avs' affiliate.