The Big Ten released its 10-game conference-only football schedule beginning as early as Labor Day weekend but cautioned Wednesday there is no certainty games will be played.

The Big Ten was the last of the Power Five conferences to announce its schedule as college football navigates how to play games amid the coronavirus pandemic.

“We’re approaching this entire process on a day-to-day basis,” Commissioner Kevin Warren said on the Big Ten Network. “We’re gathering medical information daily, we’re communicating with all of our constituents in the Big Ten and communicating with student-athletes. This will not be a straight line this year.”

Under the revised schedule, teams will play conference opponents they originally were set to meet and will have one additional cross-division game.

The regular season starts the weekend of Sept. 5 and runs through Nov. 21. There is a built-in cushion allowing for makeup games to be played, if necessary. The 10 games would be played over at least 12 weeks, with each team having two open dates. Nov. 28 also is available for makeup games.

If the coronavirus situation dictates, the season could start Sept. 12, 19 or 26.

The Big Ten championship game in Indianapolis remains scheduled for Dec. 5 but could moved as late as Dec. 19.

The conference will allow teams to begin preseason practices Friday, or earlier if a team’s season begins before Sept. 5.

At least four Big Ten football programs have been impacted by COVID-19. Outbreaks forced the shutdown of voluntary workouts at Ohio State, Michigan State, Rutgers and Northwestern.

“In making this announcement, the Conference acknowledges that there is much work to be done on our campuses, in our communities and across the country to gain control of a virus that continues to spread at an alarming rate,” the conference said in a statement. “While the Conference remains hopeful for a September 2020 start in all fall sports, including football, issuing a schedule does not guarantee that competition will occur. While our strategy is to continue planning for all fall sports, if the virus continues to spread among our students despite our many preventative measures, including testing and quarantine protocols, we are also prepared to delay or cancel competition pursuant to local and state public health orders or the recommendations of our medical experts.”

Big Ten competition start dates for men’s and women’s cross-country, field hockey, men’s and women’s soccer and women’s volleyball have been postponed through at least Sept. 5. Conference-only schedules for those sports will be released later.

The conference also released its medical policies and protocols for all sports on testing requirements, and quarantine and isolation. Testing will be managed by a third-party laboratory to ensure consistency across the conference.

Sports such as football that have a high risk of contact will have a minimum of two tests per week during the competitive season. All other sports will have a minimum of one test per week.

The player advocacy group College Athlete Unity, in a letter to the Big Ten and NCAA published on The Players’ Tribune website, called on the conference to penalize schools that don’t adhere to testing protocols and other safety measures. The group, among other things, also asked for an adjustment to players’ cost-of-living stipends to account for the increase in personal expenses related to limited access athletic facilities and reimbursement for stipends that were reduced during the summer.