Conferences are scrambling to update protocols to reflect the new variant. Most, including every Power 5 conference, have rescinded recent rules that had deemed any cancellation because of coronavirus protocol to be a forfeiture by the exposed team. What remains to be seen is whether the N.C.A.A. will amend its 25-game requirement for tournament eligibility in the event that teams are not able to reschedule enough canceled games.

No. 4 Arizona hadn’t played a game since Dec. 17 because of coronavirus exposure among its own players. Now, the Wildcats won’t play again until at least Friday because the team’s first two conference opponents, Southern California and U.C.L.A., have had exposures in their programs. Arizona will have had four games canceled or postponed at a moment many more cancellations seem imminent — and that might create a threat to the team’s postseason opportunities.

Undefeated teams across the Power 5 enter conference play with something to prove.

Three Division I teams remain undefeated. One, Arizona, played in the 2021 title game. The other two, though, have surprised opponents and onlookers by avoiding defeat, and will take double-digit win streaks into their tough conference schedules.

The Colorado Buffaloes have already won as many games — 11 — as they did during the 2020-21 season thanks to efficient shooting from forward Mya Hollingshed, a 2022 W.N.B.A. draft prospect, and Quay Miller, a transfer from Washington. The team has also used quick hands to pad its margins of victory through a fairly easy nonconference schedule: It is averaging 12.5 steals per game, which, according to Her Hoop Stats, is the ninth most among Division I teams.

The Buffaloes finished the 2018-19 season at the bottom of the Pac-12, with just one win in the conference. Two years later, they knocked off top-ranked Stanford in overtime — their first win against a No. 1 team, their first win against the Cardinal and the first of just two losses Stanford, the eventual national champion, posted that season. Now, Colorado is looking for its first winning conference season, and its first trip to the N.C.A.A. tournament, since 2013.

No. 24 North Carolina is 13-0 and has the largest average margin of victory — 32.3 points per game — in Division I. The Tar Heels have proved they can score, but their biggest asset is their defense: So far, the team has allowed only four opponents to score more than 50 points. North Carolina has yet to face a ranked opponent, but that will change on Thursday with a game against No. 5 North Carolina State. A victory over the team’s (other) in-state rival might signal a return to form for the program, which hasn’t been to the round of 16 since 2015 after competing deep in the N.C.A.A. tournament throughout the 1990s and 2000s.