Sixteen months after choosing Canada as the safest place to complete its season, the NHL now faces a series of hurdles north of the border that complicate its bid to power through the pandemic all over again.

The league postponed nine more games Tuesday -- all of them in Canada -- and cited attendance restrictions in Montreal, Winnipeg, Toronto, Ottawa and Calgary. It also moved a Jan. 12 game in Montreal between the Bruins and Canadiens to Boston.

With 80 games now postponed this season, the NHL hopes to shift the games in Canada to later in the season "when such restrictions may be eased or lifted." More than other leagues, the NHL heavily relies on ticket sales revenue.

Attendance limits are only one piece of the NHL's Canada problem.

The NFL and NBA can swiftly move to adopt shorter isolation periods for those who test positive for the coronavirus in accordance with new guidance from the U.S. Centers for Disease Control and Prevention and the two leagues also can consider not testing asymptomatic, vaccinated players.

The NHL, with seven teams north of the border, must balance stricter COVID-19 regulations set by Canadian federal and provincial authorities.

"We have always had the issue of differing rules in different jurisdictions, so it's not a new challenge," deputy commissioner Bill Daly said in an email to The Associated Press on Tuesday, hours before play resumed after an extended holiday break. "[We are] navigating choppy waters the best we can."

The CDC recommendation to trim quarantine time from 10 to five days prompted an NHL review of its virus protocols. But there is little evidence Canada is ready to move like the U.S. toward looser rules as provinces clamp down on crowd sizes and impose additional restrictions.

"It's not in the mind of the state or the population and especially not in the mind of the health field workers," said University of Ottawa professor Gilles LeVasseur, who specializes in U.S.-Canada relations. "Right now it's more, 'Let's protect, let's secure and let's close in and let's do another confinement.' ... There is not that mentality of saying that it's part of us, it's part of who we are and let's live with it."

That path in the U.S., even among other sports leagues, is causing some frustration among hockey players who would like to see the NHL relax some protocols, most notably reducing mandated absences from 10 days for those with COVID-19 symptoms.

"It seems like it's always Canada that's the reason that a lot of things don't happen, so I don't know if we're going to be able to do that," Tampa Bay Lightning forward and NHL Players' Association representative Alex Killorn said. "But it seems reasonable that we would do that and implement it as soon as possible."

Teammate Steven Stamkos said it was a fine line, while acknowledging discussion about testing less is happening around NHL locker rooms. Veteran executive Lou Lamoriello said the league and union are doing the best they can without being able to control Canadian federal and provincial rules.

"Unless we weren't playing in Canada and we didn't have teams in Canada, you could consider [not testing asymptomatic vaccinated players], and certainly it would be [considered]," the New York Islanders general manager said over the weekend. "But with the guidelines and rules of Canada, it's impossible to have happen. We wouldn't be able to have games without the testing that is required to play in Canada."

Lamoriello's Islanders had Wednesday's home game against Detroit rescheduled for virus-related reasons before the league moved on to the Canadian games.

The American Hockey League, which has 26 teams in the U.S. and five in Canada, is wrestling with the same issues. The AHL has so far postponed 61 games and is trying to play as many as possible without widespread disruption.

AHL president and CEO Scott Howson said shuffling the schedule for teams in Quebec and Manitoba is not feasible in the middle of the season, despite the possibility of games in empty arenas.

"We wouldn't consider a situation where we'd start putting those teams on the road and adjust the schedule," Howson told The AP by phone Tuesday. "They're going to play their schedule, and if they have to play a few games with 0% [capacity] then that's what they're going to do."

Having teams in Canada comes with the acknowledgement that it's more difficult for them to avoid lengthy absences.

"You're always subject to what the Canadian government's going to do, and you respect that and our Canadian teams know that," Howson said.

One option is having different testing and isolation requirements for the U.S. and Canada.

"There's arguments on both sides," Howson said. "You want the level playing field, but for us, the 26 teams that could have a less restrictive system, why should they be punished?"

The NHL is testing players, coaches and staff daily through Jan. 7 as part of enhanced virus protocols, which include a return to mask-wearing and restrictions for road teams. Taxi squads are back until the All-Star break to try to keep the season going.

As for Canada following the U.S. strategy of living with the virus, LeVasseur does not expect that shift for at least two more weeks while health officials monitor case and hospitalization numbers.

"If nothing turns out to be a catastrophe in the hospitals, then you'll have that second mentality," he said. "But until we get to Jan. 15, nothing is going to be opening to that mentality. It'll be more closed in, secure, confinement and restrictions. That is the pattern that we're going to see."

The NHL returns to game action on Tuesday night, with three contests, all housed in the U.S.

The Associated Press contributed to this report.