There have been many extraordinary aspects to the National Hockey League's return to the ice after it paused its season for the coronavirus pandemic in March. Hockey being played in August. Stanley Cup playoff games held in empty arenas echoing with artificial crowd noise. But perhaps most notable of all about the restart: How much COVID-19 hasn't impacted it.

The first week of testing in Phase 4 of the NHL's return-to-play protocol, as teams entered the "hub" zones in Toronto and Edmonton, Alberta, produced zero positive tests out of 7,703 of them. That followed Phase 3 -- when teams returned to training camps in their respective cities -- which produced two positive results among 6,874 total tests administered.

As Major League Baseball struggles to keep its season going and college football debates its future, the NBA and the NHL have restarted their seasons securely inside their respective bubbles.

But as NHL commissioner Gary Bettman cautioned, "we still have a way to go to feel any sort of gratification" about getting the protocols right.

"You've known me long enough to know that I don't sit back and try to dislocate my shoulder trying to either pat myself or anybody else on the back," Bettman said before the restart. "This is just another step in what has been a long journey and still has many, many miles to go before we get to the ultimate place that we're all striving for, which is the conclusion of the [2019-20] season and the presentation of what we all believe is the best trophy in all of sports."

As the NHL and the players enter their third week inside the bubble, here's a look at how it's worked -- as well as the challenges in keeping COVID-19 out of it.

How they planned it

First, the NHL decided that being in a bubble was non-negotiable. This was under strong urging from their medical advisers, including Dr. Isaac Bogoch, an infectious disease expert based in Toronto who consulted for the NHLPA.

"I really think the bubble approach is the best path forward, at least given this point in time during the global pandemic," Bogoch said. "Of course we know it's not going to be perfect. I think we're all talking about risk mitigation, not risk elimination. With these careful protocols, careful testing, with symptom checks, with good communication, I think we're starting to see the bubble approach -- not only in hockey, but also in basketball and soccer -- really be the best approach while these case numbers are this high, globally."

It's also important to note: The NHL did get some lucky bounces. Early on in negotiations with players, the NHL agreed to having training camps in teams' playing cities. If families weren't going to be included in the bubble, players wanted as much time at home with their loved ones. During these Phase 3 camps, players were tested regularly -- but also had the freedom to leave the rink and go to restaurants, ostensibly bars, and interact with whomever. The NHL said that in the final week of training camp, there were zero positive confirmed tests. Knowing what we know about the virus, that feels like somewhat of a miracle.

"The question was, what are people going to be doing in the 20 hours when they're not at the rink?" Bogoch said. "Of course, you can make the training facilities as safe as possible, but a lot of this boiled down to really ensuring that the players were aware that, yeah, some parts of the United States -- some more than others -- are really impacted by COVID-19 and people can get this infection. You stay at home, and you go between home and the rink. There's a lot of personal responsibility, but also responsibility to your teammates as well to make sure you don't pick this infection up and bring it to the rink. I think it's still too early to pat everyone on the back and say, 'Job well done,' but it looks like, to date, people did the right thing."

Oh, Canada

The NHL had long viewed Las Vegas as the ideal Western Conference hub location, given the proximity of the rink with luxury hotels and enough entertainment options to include in the bubble to keep players busy. However, the league swerved when cases spiked in Nevada. Instead, it chose two Canadian cities.

"I mean this sincerely, with total love and respect. I'm sitting in Toronto and I'm not trying to be a smug Canadian," Bogoch said. "Obviously, the numbers are really high in the United States, and things are in pretty decent control in Canada. Canada's population is close to 38 million people, we're getting about 200-400 new cases per day. It's not perfect, but it's pretty damn good."

What went right in Canada?

"I think what we did differently in Canada was, early on, all of the senior political leaders appreciated that this was a big deal. We listened to our senior public health leadership. When they said it was time to lock down, we locked down. When they said it was time to put on a mask, we put on a mask. When they said it was time to wash our hands, we washed our hands," Bogoch said, "and we waited. When they said it was time to open up safely and slowly, we carefully and slowly started to open up. It wasn't perfect and we certainly got some things wrong, but we didn't politicize this pandemic whatsoever."

Dr. Anthony Fauci, a key member of the White House task force on the coronavirus, expounded on the NHL's decision in an interview with ESPN Daily on July 30.

"If you look at the curve in the United States, we went up very high -- the highest in the world -- for cases and deaths. We're at about four million cases now and about 150,000 deaths," Fauci said. " If you look at the distribution of the curve -- it's important, and I think this probably impacted the decision-making process -- is that you had an increase that went way up, then it came back down. But instead of coming back down to a baseline, and by baseline I mean tens to hundreds of cases per day, not tens of thousands of cases per day, our baseline plateaued at around 20,000 cases a day and it stayed that way for several weeks. And then when we tried to open up the country, as it were, to try to get back to some normality for economic and other purposes, we saw an increase and a surge. ... So if you see that, and you're a league trying to make decisions about what the 'safe havens' are, I think you can understand their decision."

Fauci agreed with Bogoch, saying there were some "subtle cultural and other differences between the countries" that led to them being in different situations. Fauci said that includes how Canada responds to recommendations from health authorities.

"You know, the United States is culturally a wonderful place, I love it," Fauci said. "But there is a certain degree of independence of state and local [authorities] not necessarily listening to broader recommendations, and I think we saw that in the divergence and diversity of adherence to the recommendations by different states and different cities and the guidelines to reopen. I think that's a manifestation of the independence and free will to the local [authorities], compared to the mandates from centrally."

Off to practice.#MaskUp pic.twitter.com/HwBeVAJEBG

— Arizona Coyotes (@ArizonaCoyotes) August 3, 2020

How testing works

Before sending everyone into the Toronto and Edmonton bubbles, the NHL designated a few dozen categories of people who would be tested each day. They include players, everyone that comes in contact with the players, and personnel inside the arena ranging from the PA announcer to the ice crew. Among the few people who aren't tested each day by the NHL's medical staff are members of the media, third-party vendors who do setup and law enforcement.

Everyone inside the bubble is given a 30-minute window for daily testing appointments inside their hotels. The appointment windows are arranged around the team's schedule that day, including when games are played. There are 12 tables set up, with each one designated for a particular part of the alphabet. Players pick up a personalized form and then it's off for testing.

Some days feature tests in which a swab is inserted into the throat, and other days where the test is a nasal swab. Around 1,500 samples a day are collected from those inside the bubble.

DynaLife in Edmonton and LifeLabs in Toronto handle the processing of the tests. According to the Canadian Press, DynaLife set up a processing lab a few blocks south of Rogers Place, while LifeLabs processes Toronto's NHL tests at its main facility near the city's Pearson Airport. Couriers deliver the samples to both labs.

Results come back within 24 hours. The NHL and NHLPA have shared the testing numbers on a weekly basis.

Some observers had questioned how the league could have 7,000 tests administered and "no positive tests," according to its press release last week, considering how many "false positive" tests would typically have been recorded in that sample size. According to a source with knowledge of the testing, the NHL did report tests as "positive" that were later confirmed to be in error during the first few weeks of central testing of team personnel. That policy was changed before training camps were opened, and only "confirmed positive" tests are now reported. As further evidence of the bubble working so far, the source said that the league had "no positive tests, whether false or confirmed" through last Monday.

There are other layers to the NHL's COVID-19 monitoring. The bubble uses a touchless biometric identification system to take players' temperatures and track health information, created by CLEAR, the platform used for ID checks at airports and arenas.

The "Health Pass" system involved players creating accounts on their mobile devices, snapping a selfie for ID purposes. Each morning, before leaving their hotel room, they're to use the app to answer some basic health questions and get a QR code for an in-person temperature check at one of the physical kiosks. They're then either issued a red or green health pass. The NHL receives confirmation that users have satisfied their requirements for access if the signal is green.

What happens if the signal is red? Tuukka Rask of the Boston Bruins discovered that firsthand at the beginning of the round-robin when he answered a question about having a cough.

"Yeah, I had a cough so I just clicked 'yes' on the app and then all kinds of red lights started blinking, so I was quarantined for two days. They wanted to do two negative tests after that. That's it," said Rask, who returned to the Bruins on Aug. 3. "They want to be very cautious of that, if you had any symptoms."

Yet another red light that a goalie has to worry about.

"Yeah," Rask said jokingly, "I hope I don't have to get used to that."

Do players feel safe?

As captain of the St. Louis Blues, Alex Pietrangelo couldn't help but notice what was going on with his city's baseball team.

"They're in a much more difficult situation, because they have a whole season to play. So they're taking the necessary precautions when it comes to players getting it and teams having it, but it's unfortunate that they're dealing with it," he said of the Cardinals, whose COVID-19 outbreak has left nine players and seven staff members infected.

"What did we have here? Zero positive tests? So the NHL is doing something right here. They're protecting us the best that they can."

Players and coaches have spoken glowingly about the protocols put in place by the NHL and NHLPA after they agreed to restart the season. Inside the bubble, the processes have been smooth, and those inside the restricted zone feel safe.

"I think the league has done a terrific job. And the people here doing it have been terrific. We're so fortunate to be looked after the way we've been looked after here," said Columbus Blue Jackets coach John Tortorella. "It has turned into a routine, on when to go do it. I think it's been handled very well. Very safe. And very fortunate, compared to what's happening with some other people in the world."

Philadelphia Flyers goalie Brian Elliott said the routine has gotten praise from players around the league for its ease.

"You gotta make sure you set an alarm for the time when you have to go get tested -- and don't miss it. You sit there, they do the rest, and you get it all over with, in about 10 minutes' time. It's not that big of a deal," he said.

Washington Capitals center Nicklas Backstrom thanked the medical professionals running the tests. "They're doing a great job in setting up the times for us to test every morning or afternoon. It's our new routine. Everyone is adjusting. So far it's been great, and these people are heroes, here to help us out," he said.

His teammate, Tom Wilson, said the testing protocols have met his expectations.

"Maybe exceeded them. I think we're pretty lucky -- it's felt pretty normal, pretty seamless. They've done a great job making this feel safe," he said. "At the end of the day, you are in a bubble. But they make you feel that it's as normal as possible, and you don't have the risk of being in the outside world on any given day. They're working hard: the league, the [NHLPA]. They're doing everything they can to make it as safe as possible, and provide a confidence to the players that you can just worry about playing hockey, about doing your job. All the parameters and protocols put in place have done a good job so far."

What could burst the bubble?

The NHL and NHLPA agreed that players' families could join them in the bubble by the conference finals; by that point, the number of people in the bubble will have dwindled, and the NHL will be operating only out of Edmonton. It's complicated to integrate new people into the bubble, and even as the tournament began, the NHL was still working out the logistics.

As Bettman said on July 24: "It's something that the health authorities in Alberta, among others, will have to bless."

Dr. Willem Meeuwisse, the NHL's chief medical adviser, says the league has "a fairly strict procedure" for anyone entering the bubble. He says it includes the step to self-isolate for two weeks before entering the bubble. "And then once they do, we have varying degrees of quarantine that have to be served based on the type of exposure they've had, based on the type of travel that they've had to get to the bubble," Meeuwisse said. "And we have an event medical director that has the discretion to impose additional quarantine on people that they feel might be a risk."

Dr. Bogoch said he believes the protocols are thorough and can be effective in mitigating the risk. But it's still a risk, and one the NHL was willing to take.

"I think we have to also balance this, and appreciate that they are professional athletes, but they're also humans," Bogoch said. "Being away from home, from your wife, your children, your family for a couple of months will be rather challenging. So I think it's an appropriate balance that about a month or so, families can come in as long as it's done in a very safe and controlled manner."

Sharing a Stanley Cup championship with one's family is as emotional as it gets. If the NHL's bubble holds, seeing that celebration will be the first time Bettman will exhale in months.

"If there's any point where I'm going to feel substantial emotion," he said, "it'll be a sense of relief when I get to present the Stanley Cup."