The Calgary Flames were already sidelined by COVID-19.

Now the Colorado Avalanche and Florida Panthers have joined them.

The NHL announced Friday the three clubs have been shut down until after the league's holiday break, "due to concern with the number of positive cases within the last two days as well as concern for continued COVID spread in the coming days."

A total of 20 games have been postponed amid a sharp rise in players entering the NHL's COVID-19 protocol in recent weeks, including a massive jump since Monday as the fast-moving Omicron variant propels the pandemic's latest wave.

The league announced it was postponing two more Flames games — Dec. 21 versus Anaheim and Dec. 23 game versus Seattle — bringing Calgary's number to six.

The NHL said it's in the process of reviewing and revising all three teams' schedules.

The Flames' outbreak hit 32 players Friday when centre Mikael Backlund and another member of the team's support staff entered the NHL's COVID-19 protocol.

A total of 19 players and 13 club employees are currently in isolation for a team that's been hit hard by a coronavirus outbreak.

The Avalanche and Panthers also have a host of players in protocol.

The Edmonton Oilers, meanwhile, added forward Ryan Nugent-Hopkins into protocol, where he joins head coach Dave Tippett and two teammates.

The Toronto Maple Leafs cancelled their practice in Vancouver on Friday for precautionary reasons after captain John Tavares and forward Alexander Kerfoot were also added to protocol.

Toronto was supposed to play in Calgary on Thursday, but that game was cancelled.

The Leafs say all players and travelling staff were tested Thursday for COVID-19 in Vancouver. The club was informed of the test results Friday morning, and each individual will undergo additional testing.

Toronto is scheduled to play the Vancouver Canucks at Rogers Arena on Saturday before visiting the expansion Seattle Kraken on Sunday.

The Avalanche's postponed games include Saturday versus Tampa Bay, Monday at Detroit, Wednesday at Buffalo, and Thursday at Boston.

The Panthers' postponed games are Saturday at Minnesota, Tuesday at Chicago, and Thursday versus Nashville.

The Montreal Canadiens' home game against the Boston Bruins scheduled for Saturday has also been postponed.

No reason for the postponement was given, but the Canadiens played Thursday night against the Philadelphia Flyers without fans inside the Bell Centre at the request of Quebec health authorities due to the "spiralling rise of COVID-19 cases in the region."

After the game, the organization said it had been assured it will be allowed return to partial capacity at the Bell Centre beginning in January.

Meanwhile, fans attending sports events in Ontario, where capacity at large venues (more than 1,000 people) are being capped at 50 per cent due to rising COVID-19 numbers, will not be able to eat or drink in their seats.

On Friday, the province announced new Omicron-related restrictions which include a prohibition on food and drink consumption at sports arenas, cinemas and other large venues.

The new rules come into effect first thing Sunday morning.

The Canucks will also soon be playing in front of a half-empty Rogers Arena. On Friday, the B.C. government announced a string of new restrictions on events and gatherings, including limiting venues that hold more than 1,000 people to 50 per cent capacity.

B.C.'s restrictions will start Monday and last until Jan. 31.

The American Hockey League also announced three upcoming games for the Toronto Marlies have been postponed, while a COVID-19 issue with the Belleville Senators means two games -- Friday in Syracuse against the Crunch and at home Saturday against the Providence Bruins -- have been shelved.

This report by The Canadian Press was first published Dec. 17, 2021.