Colorado Avalanche center Nazem Kadri (91) celebrates with Colorado Avalanche right wing Valeri Nichushkin (13) after his goal against the New York Rangers in the third period of an NHL hockey game Tuesday, Dec. 14, 2021, in Denver. The Avalanche won 4-2. (AP Photo/David Zalubowski)

More than a quarter of NHL teams have been shut down through at least the weekend, after the Columbus Blue Jackets and Montreal Canadiens became the eighth and ninth to have activities paused because of several positive COVID-19 test results among players.

The Blue Jackets had games scheduled for Monday night at Buffalo and Thursday at home against the Sabres postponed, bringing the total to 42 across the NHL this season. The league said Columbus was shut down because of “concern with the number of positive cases within the last several days as well concern for continued COVID spread.”

Seven other NHL teams have been shut down as positive test results have risen across the league. The Detroit Red Wings and Toronto Maple Leafs were added to that list Sunday, joining the Colorado Avalanche, Florida Panthers, Calgary Flames, Nashville Predators and Boston Bruins.

The Blue Jackets canceled their morning skate Monday while awaiting COVID-19 test results, a day after calling off practice because of virus concerns. They could resume practice Sunday if cleared by the league and they are scheduled to face Toronto next Monday, though games involving teams on opposite sides of the U.S.-Canada border could continued to be postponed into next week.

The league and NHL Players’ Association said Sunday the plan was to avoid a full league shutdown, pausing team activities on a case-by-case basis and postponing all cross-border games through Thursday. The Christmas break begins Friday and runs through Sunday, with games scheduled to resume next Monday.

“We will continue to play the 2021-22 regular season schedule,” the NHL and NHLPA said Sunday in a joint statement. “Although there has been a recent increase in positive COVID test results among players, coaches and hockey staff, there have been a low number of positive cases that have resulted in concerning symptoms or serious illness.”

Roughly 10% of the league’s players are in virus protocol. The spread of delta and omicron variants across North America has made Olympic participation unlikely.

Much about the omicron coronavirus variant remains unknown, including whether it causes more or less severe illness. Scientists say omicron spreads even easier than other coronavirus strains, including delta, and it is expected to become dominant in the U.S. by early next year. Early studies suggest the vaccinated will need a booster shot for the best chance at preventing an omicron infection but even without the extra dose, vaccination still should offer strong protection against severe illness and death.

AP Hockey Writer John Wawrow contributed to this report.