BOSTON — A few hours before the Boston Red Sox played their first game of a crucial September homestand Friday night, with a chilly breeze offering a reminder of the proximity of October, Red Sox Chief Baseball Officer Chaim Bloom stood in the stands a dozen rows above the field, mask on, phone out. A few seats and a safe distance away sat trainer Brad Pearson, also hunched over his phone, as if waiting for news.

Bloom and Pearson have spent hours in impromptu meetings like these over the last week, checking their phones, hoping they wouldn’t bring news of another positive coronavirus test, even though most of the last seven days have included at least one.

Red Sox manager Alex Cora, meanwhile, has spent most of this week hoping neither Bloom or Pearson’s names popped up on his phone, knowing full well that any early morning text message probably meant he would need to shuffle his lineup yet again.

Boston’s Jarren Duran slides into home plate to score against the Yankees last month. The Red Sox added Duran to the COVID-19 list Friday. AP file photo

Friday, Bloom and Pearson learned before the game that speedy rookie Jarren Duran was experiencing symptoms. Cora pulled Duran from the lineup and told him to stay away from the team. By the time the Red Sox had beaten the Cleveland Indians, 8-5, Duran had tested positive, the ninth Red Sox player sidelined by a COVID-19 outbreak that simply won’t go away.

Outbreaks like theirs are an unyielding part of Major League Baseball’s reality, even as many around the game hoped vaccine availability and well-honed protocols would allow the season to proceed without too many of them — especially this time of year.

But like so much of the country, the Red Sox are dealing with a surge of COVID-19 cases that threatens to undermine all their progress, a surge that probably could have been mitigated, if not avoided, if everyone on their roster were willing to get the vaccine.

The Red Sox are one of seven teams that have not reached the 85% vaccination threshold at which protocols relax, one of several teams dealing with the fact that about 13% of Major League players are not vaccinated, according to MLB — a number far lower than it is nationwide, but a number that is still relatively high considering the amount of time, money and analysis professional baseball teams spend on the health of their players.

“I wish everybody in our organization were vaccinated, and for that matter, everyone, period, who’s eligible,” Bloom told reporters this week, who also said he’s lost plenty of sleep wondering what he and his staff could have done differently to convince more players to get the shot.

But the Red Sox aren’t the only team navigating COVID-19 issues. Cubs President of Baseball Operations Jed Hoyer, an outspoken proponent of vaccination, tested positive for the virus Friday along with Cubs manager David Ross, both of whom were vaccinated, both of whom are now in isolation, according to the team.

Many of the recent COVID-19 outbreaks, including Boston’s this week, have included breakthrough cases — instances in which a player tests positive despite being vaccinated, like infielder Kiké Hernandez did. So while Major League Baseball and many of its teams are pushing vaccination, everyone acknowledges it does not universally protect against losing players to the COVID-19 injured list.

Still, in addition to helping prevent teams from losing players, vaccination also limits the number of players lost when a case occurs: If a player is vaccinated, he does not need to quarantine if he is deemed a close contact of someone who tests positive. If he is not vaccinated, he must quarantine for up to seven days.

“There’s no real way to know if it would have been different if we had had a higher vaccination rate or not,” Bloom said of his team’s outbreak. “In this case, I don’t know if that’s knowable, and I don’t think it’s helpful to play the what-if game.”

But given that the playoffs are weeks away, the “what-if” game is somewhat unavoidable. Because while the Red Sox have somehow managed a 5-3 record since positive tests started rolling in, who knows what an outbreak like that could bring if it preceded, say, a wild-card game showdown with the New York Yankees or a quick five-game division series.

As it is, the timing was devastating for the Red Sox, who spent August falling into third place in the American League East for the first time all season. But what if, instead of last Friday as they began a crucial road trip, Hernandez tested positive at the beginning of a playoff series? Infielder Christian Arroyo was required to quarantine because he was a close contact of Hernandez, something the league only requires if that close contact is not vaccinated.

As it happened, Arroyo tested positive two days later. Within five days, closer Matt Barnes, reliever Hirokazu Sawamura, pitcher Martín Pérez, and infielder Yairo Muñoz had also tested positive — rendering all of them unavailable for more than a week. All-star shortstop Xander Bogaerts not only tested positive, but had to be pulled from the field in the middle of the game because of a late-arriving test result.

Reliever Josh Taylor had been identified as a close contact in need of quarantine. By the time Duran tested positive Friday, nine players and three coaches were away from the team, some still waiting out quarantines in Cleveland or Tampa Bay, and Cora was piecing together lineups from the ever-changing list of the unscathed.

The Red Sox have altered their day-to-day routines to account for the outbreak. They are testing more, adjusting report times to limit close contact in the clubhouse, shifting hitting groups, and planning meetings — even impromptu ones among management to discuss the latest test results — outside.

But while the Nationals, Twins and others experienced postponements due to COVID-19 outbreaks earlier in the season, Bloom told reporters this week that he has not been a part of conversations to postpone games because of this most recent outbreak. The baseball season is, in some ways, past the point of no return — at least in terms of making up games. Like so much of the country, Major League Baseball is no longer working around the pandemic, but rather pushing through it.

And given that a COVID-19 outbreak would be even more catastrophic during the postseason, front office types will almost certainly be asking an uncomfortable question: How does a borderline player’s vaccination status affect his position for a spot on a playoff roster?

“I think that’s going to have to be a conversation in the industry that we step back and have, and obviously there’s a lot of different levels to that conversation including the rights of our players and what that should mean,” Bloom told reporters this week.

While mandatory vaccination for players has long been a no-go for the players’ union, many organizations are considering and/or implementing vaccine mandates for other team employees. The league office mandates vaccinations. The Nationals and Baltimore Orioles have set deadlines by which team employees must be vaccinated or part ways with the organization. The San Francisco Giants already have a vaccine mandate for employees who come into the office, though many team employees are still working from home.

In the Nationals’ case, the mandate will almost certainly result in a parting of ways with former big league player, manager and current executive Bob Boone, father of Yankees’ manager Aaron and former all-star Bret. While the Nationals say Boone is resigning rather than comply with the mandate, Boone insists he is not resigning, suggesting instead that he has been forced to leave the organization. Either way, the outcome is the same, and it is jarring: One of the Nationals longest-serving front office stalwarts will be gone because of his unwillingness to get the shot.

Similar unwillingness on the part of players could contribute to COVID-19 outbreaks down the stretch, with months of work and sweat and tears on the line. Front offices and coaching staffs spend months and millions investing in their rosters and training staffs, trying to stave off anything that might undermine it all in October. The question for the Red Sox and others over the next few weeks is how much the players, themselves, are willing to inoculate themselves against those contingencies, too.