In the Big 10, assuming team+staff is about 140 people, about 10 or more being positive would cancel the week.
It is possible that a Big 10 team here or there gets knocked out for a week, but my guess is that there won't be a lot of that because of the precautions.
If a player tests positive, he is out of games for 21 days (about 1/3 of the Big 10 season) and will be monitored for heart inflammation.
(More specifics. In the Big 10, there will be daily antigen testing. Positives on antigen test need to be confirmed by PCR test. If more than 5% of tests come back positive and more than 7.5% of team+staff is positive, the team must cancel that week's game.)