Face masks were as prevalent as pucks throughout the NHL this past season, but documents show Canadian health officials wanted the league to take additional steps to prevent the spread of COVID-19.

The league introduced a number of protocols in a bid to get back on the ice, including the daily testing of players and staff, rules around physical distancing and masks, and limiting the contact teammates could have away from the rink.

Still, documents released to The Canadian Press under the Freedom of Information Act show health officials "strongly" recommended the league adopt additional measures before green-lighting its return.

After receiving a draft of the NHL's return-to-play protocols, health officials from Alberta, British Columbia, Manitoba, Ontario, Quebec and the Public Health Agency of Canada sent a joint letter to commissioner Gary Bettman on Dec. 23, 2020, urging the league to either add regular testing for the close contacts of players and staff to its protocols or use a "bubble model" similar to what the league created in Toronto and Edmonton to finish out the 2019-20 season.

"Should any iteration of the bubble model not be achievable for the NHL, we would recommend that the start of the season be delayed for a few weeks to allow for disease rates to drop and our health systems to recover," the letter read.

The health officials -- including Alberta's chief medical health officer Dr. Deena Hinshaw, B.C.'s provincial health officer Dr. Bonnie Henry, Manitoba's chief provincial public health officer Dr. Brent Roussin, Ontario's chief medical officer of health Dr. David Williams, Quebec's national director of public health Horacio Arruda and Dr. Howard Njoo, deputy chief public health officer with the Public Health Agency of Canada -- also asked for the NHL's help in getting Canadians on board with preventing transmission of COVID-19.

"The NHL is well positioned to take on a strong role in promoting health and safety measures, critical to reducing the spread of COVID in our provinces. We would be greatly appreciative of visible leadership the NHL could provide over the first few months of 2021 in a time when our collective efforts to contain the virus will be critical to sustaining our health systems across the country," the letter read.

Bettman replied on Dec. 24, saying the league had already incorporated input from various Canadian public health agencies into its protocols.

"We do not believe that our return to play plan poses a material risk to the health and safety of everyday Canadians," his letter said.

Bettman noted that players, staff and coaches would be tested daily and said the league would "make best efforts" to provide families and other close contacts with access to tests when requested. He added that the NHL's protocols had been updated to include testing for a player's close contacts for 14 days if the player tested positive for the virus.

The letter also noted that the NHL had changed its schedule to limit how often a team travels in or out of provinces, and said that the addition of a "taxi squad" would limit cross-border travel.

"We do not believe that either a 'bubble model' for the beginning of the season, nor a multi-week delay before beginning play, are feasible; nor do we think they are necessary," Bettman said.

"We do believe in our ability to stage a successful return to play without employing such measures by ensuring appropriate risk mitigations are in place and that our personnel strictly comply with those mitigations."

The commissioner added that the league was "enthusiastically embracing" the health officials' request to encourage Canadians to take steps to mitigate COVID-19 transmission.

"The league, our clubs and our players will commit to assuming a strong and visible role in promoting the health and safety measures in reducing the spread of COVID-19 in your provinces," he said.

The health officials sent another joint letter to Bettman on Dec. 25 saying they supported the NHL's return to play in Canada. The league began its condensed 56-game season on Jan. 13.

The NHL released numbers on June 28 showing it had administered more than 350,000 COVID-19 tests over the course of the season, with 119 players receiving "confirmed positives."

The virus forced 12 teams to shut down over the course of the season, postponing 55 games.

The Vancouver Canucks experienced the league's worst outbreak in late March when an aggressive variant swept through the locker room.

Twenty-one players and four members of the coaching staff tested positive for the virus, with many experiencing symptoms that included extreme fatigue, fever, chills and shortness of breath. Loved ones also fell ill, including wives and children.

Vancouver had several games postponed and didn't play for more than three weeks.

The team said an investigation and contact tracing found the outbreak was sparked by a single unnamed individual picking up the infection in a "community setting" that was later identified as a "public exposure location."

The Montreal Canadiens also had four games postponed in late March after two players were added to the COVID-19 list.

Interim head coach Dominique Ducharme had to isolate, too, after testing positive for the virus on June 19. He watched his team complete its semifinal series against the Vegas Golden Knights from home and missed the first two games of the Stanley Cup Final against the Tampa Bay Lightning.