By Michael Hurley, CBS Boston

BOSTON (CBS) — For a while there, things were going pretty smoothly. While an occasional case of COVID-19 might have disrupted sports to some degree, the issues have generally been minor. The word “outbreak” didn’t get bandied about all that often, games were not being canceled, and if you squinted and held your breath, things looked borderline normal across the sports landscape.

But that changed in a hurry this week, as COVID has once again made itself stand front and center in the sports world. And it’s really only taken a few days to get there, as all three in-season major sports leagues have been impacted this week.

In the NHL, the Calgary Flames have shut down for the time being after nine players and a staff member have tested positive for the virus. They’re not alone, though. The Bruins, who played the Flames on Saturday night, placed Brad Marchand and Craig Smith in COVID protocol on Tuesday. The Carolina Hurricanes had six players and a trainer test positive, with three of those members of the organization stuck quarantining in Vancouver. The Canucks had a player — Tucker Poolman — pulled out of a game on Tuesday night after a positive test, after three of his teammates also tested positive. The Islanders placed Mathew Barzal in COVID protocol, too, one of 18 players added to the COVID-19 list during the day.

In the NFL, the league saw 75 players test positive in a two-day span this week. Considering the league only had 110 positive tests from the start of the season through the end of November, that is just a massive number. The Rams and Browns have closed their facilities and entered intensive protocols due to a high number of positives. Cleveland is on a short week, too, with their game scheduled for Saturday afternoon. In L.A., star cornerback Jalen Ramsey tested positive on Monday, preventing him from playing against the Cardinals. Star receiver Odell Beckham Jr. has since tested positive as well. Browns head coach Kevin Stefanski — who was vaccinated and received a booster shot — tested positive for the second time this calendar year, as did eight players who were also vaccinated.

Then, in a perfect encapsulation of the current times, Baker Mayfield tested positive for COVID-19 while this story was being written. (Patrice Bergeron was placed in COVID protocols by the Bruins nine minutes after this story was published.)

That figures to be a big one, too. A starting quarterback potentially being out for a nationally televised game has a way of catching a lot of people’s attention.

(The NFL may also have a problem with fake vaccine cards, as evidenced by Antonio Brown’s situation coming to light. The league, though, doesn’t seem too eager to fully investigate that matter.)

And in the NBA, reigning Finals MVP Giannis Antetokounmpo was placed in health and safety protocols on Tuesday, while two other Bucks players have also been placed in the protocols. The Bulls have 10 players in the protocols, which forced the postponement of multiple games for Chicago. The Brooklyn Nets are on the edge of being in that situation, too, as they played — and won — on Tuesday night despite seven players being in the health and safety protocols.

It figures to get worse, too. An ESPN report noted that league officials “expect that more players will have to enter health and safety protocols after Christmas and New Year’s due to the likelihood of increasing cases of COVID-19 nationwide as people gather indoors for the holidays.”

Clearly, COVID is back to causing problems for sports leagues again. How they navigate out of it figures to be tricky.

Update: Sacramento Kings head coach Alvin Gentry has since tested positive, while the number of Calgary Flames added … 17 people to COVID protocols. The NFL now has seven teams in intensive protocols.

On the positive front, the positive cases don’t seem to be causing health crises of any kind. With most professional athletes and coaches having been vaccinated, few cases have resulted in concerning illnesses. For the sake of humanity (and common sense), surely everybody is hoping that remains the case.

In that sense, the positive cases appear to be more of a nuisance than an emergency. But it’s nevertheless a rather large nuisance, as the current rate can and will lead to cancellations and postponements. For the NFL, where rescheduling games at this point of the season is extremely difficult and at times impossible, that is problematic. In the NHL, where players are supposed to be getting a break for the Beijing Olympics in February, the league may be forced to rethink its participation in China if postponements continue to stack up.

There’s also the issue of attendance. Leagues have happily allowed full-capacity crowds back into their buildings this year, generating revenue that was sorely missed last season, when arenas and stadiums were either empty or hosting limited capacities. If positive cases rise in the general population at a rate similar to the players, municipalities will surely be taking a look at their attendance policies. Owners who badly want that ticket and concessions revenue will not be excited about any potential changes there.

Obviously, the world of sports — and the world in general — is in a better spot than a year ago. More knowledge and experience with the virus has alleviated some of the fear and uncertainty that used to rule such situations.

At the same time, the virus is still serious, and it still poses a public health risk. Medical experts have indicated that in due time, the world will manage to live with COVID, just as it does with, say, the flu. But we’re not there yet. And while sports are far from the most important aspect of the issue, the leagues are some of the most profitable and popular businesses in North America. The plan since COVID hit in March 2020 has basically been to figure things out as they happen, and that will have to remain the case in the days, weeks and months that lie ahead.