As professional sports continue plotting potential returns to play, one major hurdle will be doing so in a way that meets public health requirements in every province or state that hosts games.

On Monday, Ontario began outlining some of those requirements , including the need for a "consistent two-to-four week decrease in the number of new daily COVID-19 cases," said Premier Doug Ford.

"I don't believe when sports come back they're gonna come back with a full stadium anywhere in North America. I think there'll be empty stadiums at the beginning," Ford said.

However, containing the virus even within an environment that only includes players and essential staff will also prove difficult, according to federal health minister Patty Hajdu.

"There is a high degree of contact and a high degree of exhalation and a high degree of, sort of, potential of droplets, if you will. Spit and all kinds of stuff, you know, entering each others bodies and that makes that particular sector very challenging," Hajdu said.

WATCH | Ford, Hajdu on return of sports:

Canada's Health Minister Patty Hajdu says the return of sports is going to be very challenging and Ontario Premier Doug Ford believes when sports return it will be with empty stadiums. 3:09

The NHL's most recent return-to-play model included using multiple cities as hubs where each division would congregate and play as many as three games per day. The NBA said on Monday team training facilities wouldn't reopen until May 8 at earliest.

But as was the case when the NBA shut down following Rudy Gobert's positive diagnosis, Hajdu said the possibility of a player testing positive could "take out" however many teams are playing within that specific hub.

"I see professional sports much like the same as any other sector. There will have to be considerations that are based on science, that are worked out with the employer and with the employees, in this case, to make sure that the people in that sector are kept safe and the people that are interacting with that sector are kept safe as well," Hajdu said.

Dr. Theresa Tam, the Chief Public Health Officer of Canada, invited leagues to come up with plans as soon as possible, though sports haven't been specifically discussed at the federal level yet.

"I think the idea is to encourage people to think ahead, submit their plans to public health, and see if it would actually meet public health requirements. But I have to admit that we haven't actually specifically talked about that setting, as of yet," Tam said.