After the 2020 college football season once seemed in jeopardy, four of the five major conferences will play this fall. The Big Ten became the first Power Five conference to postpone its season Aug. 11, but the league reversed course a month later and will begin playing in late October. The Pac-12 is only major conference without plans for the fall. Two other conferences in the top-tier Football Bowl Subdivision have also decided against playing a fall season.

The novel coronavirus, which has killed at least 193,000 people in the United States, shuttered college sports in March, canceling the NCAA men’s and women’s basketball tournaments and abruptly ending many athletes’ careers.

Schools and their leagues prepared for a return to competition this fall, and football players arrived on campus in June for voluntary workouts. But as the season approached, and the nation had yet to contain the virus, decision-makers worried about whether they could safely hold a season. The availability of tests and advanced cardiac screening has eased some of those concerns.

The ACC and Big 12 have already begun playing, and the SEC will join them in late September. Even the Pac-12 is moving closer toward playing following the Big Ten’s reversal. While a few leagues are not playing and fan attendance is either limited or not allowed, this fall will somewhat resemble a typical college football season.

Here’s what you need to know:

Which college football teams won’t play this fall?

As of now, 38 of the 130 FBS teams will not play football this fall. The Pac-12 announced its decision Aug. 11 just after the Big Ten’s initial postponement. Outside the Power Five conferences, the Mid-American Conference and then the Mountain West Conference, which include 12 teams apiece, have both canceled their fall sports seasons. However, Air Force, a member of the Mountain West, will play games against Navy and Army this fall.

Old Dominion, a member of Conference USA, announced that it will not play this fall, even though its league plans to hold the football season as scheduled. Two independents — the University of Connecticut and New Mexico State — have decided against playing sports this fall. After all the Power Five conferences adjusted their 2020 schedules, independents scrambled to find opponents.

The University of Massachusetts postponed its fall season Aug. 11, but the school reversed the decision in September after the Big Ten announced plans to return to play. UMass, which does not compete in a college football conference, said in a news release that the team will “play a limited number of football games this fall.”

The Big Ten and SEC are playing conference-only slates, while the Big 12 and ACC decided to leave space for one nonconference game.

Outside the Power Five, the Sun Belt Conference, the American Athletic Conference and Conference USA are all playing this fall.

Will teams play in the spring?

Conferences that have canceled the fall seasons are hopeful their teams will have an opportunity to play during the 2020-21 academic year. It’s unclear when a season would begin or how it would work. The conferences that have announced fall cancellations also expressed their intention to explore competitive opportunities during the spring semester. U-Conn. was the only school that announced that its football team would not compete during the 2020-21 school year.

However, the logistics of a spring football season could be complex. The NFL scouting combine typically begins in late February before the NFL draft in April. Even if that timeline is adjusted to accommodate a spring season, some NFL-bound stars might choose to opt out rather than risking injury by playing.

There are also concerns about the feasibility of holding the 2020 and 2021 seasons during the same calendar year because of the physical toll that could take on athletes.

When asked on Big Ten Network in August if a spring season could be held, former Ohio State coach Urban Meyer said: “No chance. You can’t ask a player to play two seasons in a calendar year.”

It’s unclear how well the country may have contained the coronavirus by January or whether a vaccine will be available. Given that some conferences felt it was unsafe to proceed with a fall football season, progress in slowing the spread of the virus would be necessary for the resumption of college sports.

Athletic departments will face significant revenue shortfalls without the money generated by college football. If a spring season could help recoup some of those losses, that would be advantageous to these schools.

Can teams play in other conferences if their schedule has been canceled?

Because of the contractual agreements between schools and their conferences, this would be unlikely. CBS Sports reported that a conference’s television contracts could prevent a team from leaving its league for a year because those agreements tie a school’s broadcast rights to its conference.

When the Big Ten appeared to be heading toward postponement, Nebraska Coach Scott Frost said: “Our university is committed to playing no matter what, no matter what that looks like and how that looks. We want to play no matter who it is or where it is. So we’ll see how all those chips fall. We certainly hope it’s in the Big Ten. If it isn’t, I think we’re prepared to look for other options.”

In a joint statement Aug. 11, Nebraska Athletic Director Bill Moos and Frost said: “We are very disappointed in the decision by the Big Ten Conference to postpone the fall football season, as we have been and continue to be ready to play.”

In an interview on Big Ten Network, Commissioner Kevin Warren was asked whether it would be possible for a member of the conference to play elsewhere this fall. Warren would not directly answer that question and said the comments from coaches came as a result of emotion and passion. Warren later told Yahoo Sports that Nebraska could not join another league for the season and remain in the Big Ten.

“We have 14 institutions in the Big Ten Conference,” Warren said on BTN. “We’ve been together. I plan for us to continually be together and work collectively to make sure that we’re doing everything that we possibly can to make sure that we keep our conference very strong academically and also very strong athletically.”

By Aug. 13, two days after the Big Ten canceled its fall season, Nebraska’s chancellor and the university system president released a joint statement that said Nebraska is “a fully committed member of the Big Ten Conference.”

How will this affect players’ eligibility?

Athletes typically have five years to use four seasons of eligibility. The NCAA’s Division I Council recommended Wednesday that all fall-sport athletes, regardless of how many games they play during the 2020-21 academic year, receive an extra season of eligibility and an additional year to complete their eligibility. These recommendations were approved Friday by the NCAA’s Board of Directors.

Seniors who return for an extra season during the 2021-22 school year would not count toward the team’s scholarship limits. That is necessary because schools already have classes of athletes committed to join the program on scholarship next year, and those offers are made with the assumption that a certain number of players would have exhausted their eligibility this season.

The NCAA faced a similar issue earlier this year when the coronavirus cut short the seasons of spring-sport athletes. The Division I Council voted to grant all those athletes an additional year of eligibility, but schools can self-apply the waiver, meaning the institutions get to choose who receives extra eligibility. Some schools chose not to apply the waiver, usually citing financial concerns.

Could players sign a liability waiver to ease some of the universities’ concerns?

No. The NCAA Board of Governors said last week that schools cannot require athletes to sign liability waivers related to athletics participation during the coronavirus pandemic. At a recent Senate Judiciary Committee hearing, NCAA President Mark Emmert said he is “categorically opposed” to schools having athletes sign these waivers.

Upon returning to campus, some schools had athletes sign pledges that said they would adhere to health and safety protocols, such as wearing masks.

What has been the response to the debate over holding games?

Some players have expressed concerns about playing this season and the long-term effects of the coronavirus. Dozens of players opted out of this season.

But in the days leading up to the Big Ten’s and Pac-12′s decisions, numerous athletes, coaches and politicians publicly pushed for a fall football season. Power Five players banded together and shared a social media message featuring the hashtag #WeWantToPlay. President Trump tweeted his support for a season and wrote: “The student-athletes have been working too hard for their season to be canceled. #WeWantToPlay.”

For the teams and leagues without fall plans, the push to play grew as other conferences began playing. A small group of parents held a rally outside the Big Ten’s headquarters. Ohio State quarterback Justin Fields, one of the Big Ten’s best players in the conference, urged conference to reverse its decision with a petition. Some coaches publicly criticized the conference’s decision.

Trump spoke with Warren in early September. In the weeks leading up to the Big Ten’s reversal, Trump advocated that the conference return to play as soon as possible. The conference includes several key battleground states in Trump’s reelection campaign, including Wisconsin, Michigan and Pennsylvania. After the Big Ten’s announcement, the White House quickly claimed victory.

Trump tweeted: “Great News: BIG TEN FOOTBALL IS BACK. All teams to participate. Thank you to the players, coaches, parents, and all school representatives. Have a FANTASTIC SEASON! It is my great honor to have helped!!!”

When will college basketball begin?

Tip-off for the men’s and women’s Division I college basketball seasons was moved to Nov. 25, a delay of more than two weeks from the original start date, for precautionary reasons, the NCAA recently announced.

“This new season start date near the Thanksgiving holiday represents the optimal opportunity to successfully launch the basketball season,” said Dan Gavitt, the NCAA senior vice president of basketball. “It is a grand compromise of sorts and a unified approach that focuses on the health and safety of student-athletes competing toward the 2021 Division I basketball championships.”

If colleges are canceling seasons, why can professional leagues play?

Some professional leagues in the United States have returned to play successfully by housing their players and competing inside a bubble — a controlled, insular environment that keeps teams away from the public. Major League Baseball’s model, in which players are not strictly isolated and teams travel to other cities for away games, is similar to how college football would operate this fall. Multiple MLB teams have dealt with coronavirus outbreaks.

A bubble setup is not feasible in college football, conference and university leaders have said throughout the summer. The cost would be significant. But even if Power Five conferences were willing to devote the resources needed to hold a season, isolating players from the university’s general population would run counter to the NCAA’s long-standing view that college athletes should be part of the campus’s academic and social community. A bubble would essentially force the NCAA to admit that college athletes are different from other students, which could contribute to the erosion of the college model anchored by amateurism.