The college football season, a rite of autumn and a revered American institution uninterrupted for 150 years, veered this week toward a grim fate as the novel coronavirus continued to surge.

When the spread of the virus put virtually all sports on hold in March, many major college football leaders viewed the prospect of playing this fall, perhaps even in full stadiums, through an optimistic lens. They had time and a financial imperative: The entire collegiate athletic system depends on the revenue generated by the sport’s lucrative television rights deals and ticket sales filling enormous on-campus stadiums.

Those hopes, which began to dissipate amid a flurry of positive tests as players returned to campuses for voluntary workouts, might be vanishing after a week of ominous signs and dire indications. On Wednesday, the Ivy League declared it would suspend all sports in the fall, a warning sign that gained resonance Thursday, when the Big Ten announced it will play only conference games in 2020. Big Ten Commissioner Kevin Warren acknowledged the move may be incremental in the eventual cancellation of the season for the conference of tradition-steeped programs such as Ohio State and Michigan.

“We may not have college sports in the fall,” Warren said Thursday in an interview on the Big Ten Network. “We may not have a college football season in the Big Ten.”

On Friday, the Pac-12 followed suit, announcing fall sports would be conference-only and pushing back the start of mandatory athletic activities “until a series of health and safety indicators, which have recently trended in a negative direction, provided sufficient positive data to enable a move to a second phase of return-to-play activities,” the conference said in a news release.

The Pac-12’s decision “doesn’t mean there’s [definitely] going to be football in the fall,” Oregon State Athletic Director Scott Barnes told Portland television station KOIN. Adding to the sense of dread, the Pac-12 announced later Friday that Commissioner Larry Scott, 55, had tested positive for the coronavirus.

Other conference leaders and campus representatives soon will face the same wrenching considerations, and many have scheduled meetings to arrive at high-stakes decisions. A season without college football would have grave financial consequences. Athletic departments already have felt the financial squeeze of the coronavirus, evidenced this week by Stanford, one of the nation’s most decorated athletic departments, cutting 11 varsity sports. The loss of football revenue would exacerbate a problem that began with the cancellation of the lucrative NCAA men’s basketball tournament in March.

College football in some ways had apparent advantages in returning to play. Athletes are not unionized and receive no compensation beyond scholarships and a small stipend, which gives administrators and coaches tremendous power. But as the United States could not halt the coronavirus in late spring and into the summer and as sports leagues attempted to forge a path ahead, big-time college football was particularly troubled.

Playing the sport demands constant proximity to and physical contact with others. Teams are spliced into campuses struggling to determine a course for fall academics. Programs are strewn from Honolulu to Boston, in sleepy towns and huge cities. Central leadership does not exist.

While administrators cling to hope that they can save a teetering season, they are caught in a national crisis over which they have little control. Case counts and positive-test percentages continue to rise across the country and acutely in states such as Texas, Florida and Arizona.

“College football can’t be isolated from what’s going on as a nation as a whole,” said Johns Hopkins infectious-disease expert Amesh Adalja, a member of the NCAA’s coronavirus advisory panel. “The events of the past several weeks have really made the calculation a lot different than it was a month ago in early June, when we were thinking about what measures to put in place. It just becomes much, much more difficult when you’ve got rising outbreaks in many states.”

The sport’s leaders are scrambling to create contingencies. But Adalja pointed to several factors that make even trying to plan for an altered season dicey. Quarantine measures in various states may restrict travel. In some states, testing capacity has been stretched to the point that turnaround time for prior-to-competition testing would be impractical and the ethical choice of dedicating hundreds of tests to healthy athletes is fraught.

Excising nonconference games, Warren said, was an option chosen to salvage any kind of season. By playing only league games, the Big Ten can fully control its schedule, allowing it to postpone games, restrict travel or reschedule matchups with autonomy.

“One of the things that was most important to us was the flexibility of the operations,” Warren said.

The decision compelled the NCAA to offer tepid support with a wan statement that reinforced one of college football’s greatest challenges in a pandemic: No one is really in charge. The NCAA provides guidance, but conference commissioners make decisions, and those are often heavily influenced by power brokers who range from television executives to coaches. The chaotic patchwork of fiefdoms typically adds to the sport’s flavor, but in a pandemic, it makes necessary steps — particularly uniform testing — impossible.

“As the COVID-19 pandemic continues to impact college sports nationally, the NCAA supports its members as they make important decisions based on their specific circumstances and in the best interest of college athletes’ health and well-being,” the NCAA’s statement read.

The elimination of nonconference games may help the Big Ten and Pac-12 have a season simply by shortening it. Each league could play its full schedule by starting the season as many as six weeks late, buying the conferences a little extra time. But even those most incentivized to play recognize the implications.

“Two months ago I was cautiously optimistic, but I’ve lost that,” Ohio State Athletic Director Gene Smith said on a conference call with reporters. “ … I am concerned we may not be able to play.”

Other leagues could soon follow suit. Multiple reports suggested the Atlantic Coast Conference probably will cancel nonconference games, making an exception for Notre Dame (which is independent in football but an ACC member in other sports).

The most wrenching choice may belong to the Southeastern Conference, whose football teams are embedded in the culture of and are vital economic engines for the South. Programs such as Alabama, Georgia and Louisiana State are national powerhouses and local obsessions. The conference has yet to take any steps toward reducing or canceling the season, but a spokesman said league officials will meet with campus leaders “to determine the best path forward related to the SEC fall sports.”

“We recognize the challenges ahead and know the well-being of our student-athletes, coaches, staff and fans must remain at the forefront of those decisions,” the SEC spokesman said.

Those who held out optimism met a reckoning this week. Programs in the Ivy League and those in the sport’s major conferences share as much in common as a pop gun and a rocket launcher, but Wednesday’s announcement still reverberated because the Ivy League had presaged broader decisions before. In March, the Ivy League canceled its men’s and women’s basketball tournaments to much criticism. About 48 hours later, the entire NCAA tournament, one of the country’s grandest sporting spectacles, had been called off.

As the Ivy League suspended fall sports, Ohio State and North Carolina shut down voluntary team workouts on campus after a rash of positive tests. Those actions raised a gloomy question: If football teams can’t safely make it through informal practices, how can they practice in full?

Notre Dame Athletic Director Jack Swarbrick, one of the sport’s leading influencers, added to the bleak outlook. On Thursday, he told ESPN the past two weeks have made him pessimistic about starting on time, and it is now “less likely” the sport can launch as usual.

“We have to shift our allocations a little bit — a little more time on planning the alternatives and a little less time on planning routine go-forward,” Swarbrick said.

Adalja said he could see a college football season unfolding in partial form, with some schools sidelined because of their geography. But even that is problematic, he said, because of the high chance of outbreaks popping up in new places.

The overall picture pointed to a sobering conclusion: College football, one of America’s most popular pursuits, is staring into the abyss. The country had many months to save this season, and now time has nearly run out.

In June, as cases came down, Adalja believed college football would be possible. The approach of test, trace and isolate had been established as a successful method to inch back toward normalcy.

“It’s simply impossible, it seems, for certain places to put in place the infrastructure to do that,” Adalja said. “If you want to have some semblance of normalcy, you have to get this right. We have to acknowledge the failure. It’s very baffling to many of us that this continues to happen. You can’t separate sports from the society in which it’s being played in.”