The forward will be reevaluated for a lower-body injury sustained in a 3-1 loss to the Los Angeles Kings at Staples Center on Monday,
"It may be not that serious, and that's what we're hoping for," Bednar said. "But [he has to] get checked out and obviously, we have to see what he feels like here today."
The Avalanche (41-20-8) were off Tuesday and will have a morning skate before their home game against the New York Rangers on Wednesday (10 p.m. ET; ESPN+, ALT, MSG+, NHL.TV). Colorado trails the St. Louis Blues by two points for first place in the Central Division.
It's not known how or when MacKinnon was injured; he had one shot on goal in 11:37 of ice time. The Kings led 2-0 when MacKinnon went to the locker room at 15:00 of the second period.
"I don't think it was just one incident," Bednar said. "I just think he went out to play and it didn't feel great sometime during the first period, and [he] decided just to call it quits."
MacKinnon leads the Avalanche and was tied with Artemi Panarin of the New York Rangers for fourth in the NHL with 93 points (35 goals, 58 assists).
Colorado was already without several key players, including forwards Andre Burakovsky (lower body), Mikko Rantanen (upper body) and Nazem Kadri (lower body), defenseman Cale Makar (upper body), and goalie Philipp Grubauer (lower body).
The Avalanche have 13 games remaining in the final 25 days of the season. Beginning Wednesday, they play every other day until the season ends April 4.
"We have a lot of guys who are kind of battling those little injuries right now," Bednar said. "It's that time of year. If you look at the schedule and the amount of games we're playing, we've been trying to give them as much rest as we possibly can and just go game days only and days off in between.
"That's the way we feel like we have to run here until the end of this, especially with all the injuries we have. We're just trying to manage everyone's minutes and give them as much rest as possible. But the injuries are starting to pile up, so hopefully we're going to get some guys back here this week."
