A little convoluted, but here are the best and worst case Pac-12 tourney seeding scenarios for the top four teams. Each has one game left on Saturday except Cal, which can only sit and wait. Scroll all the way down for the tiebreaker rules.

Oregon (23-7, 12-5)
Best case: No. 1 seed and an outright Pac-12 title. The Ducks beat Utah while UCLA loses to Washington, dropping the Bruins to a three-seed. Cal would be a No. 2 seed because it has a season sweep of Oregon (see second tiebreaker).
Worst case: No. 3 seed. Oregon loses at Utah, while UCLA clinches an outright Pac-12 title with a win at Washington. Cal would get the No. 2 seed.

UCLA (22-8, 12-5)
Best case: No. 1 seed and outright Pac-12 title. The Bruins beat Washington in Seattle for the first time since 2004 as Utah upsets Oregon. Cal gets No. 2 seed for sweeping the Ducks.
Worst case: No. 3 seed. Lose to Washington. Oregon and Cal both hold head-to-head tiebreakers over UCLA in the event of a three-way tie.

Cal (20-10, 12-6)
Best case: No. 1 seed and shared Pac-12 title. Both Oregon and UCLA lose on the road. The Bears own the head-to-head tiebreaker with a 3-1 record against the two teams. If Arizona also ties with 12 wins, Cal still leads with a 4-1 record.
Worst case: No. 3 seed. Oregon and UCLA both win on Saturday. Cal gets a head-to-head tiebreaker against Arizona should the Wildcats beat ASU.

Arizona (23-6, 11-6)
Best case: No. 4 seed and four-way shared conference title. Arizona beats ASU in its season finale as Oregon and UCLA both lose on the road. The Wildcats still lose all tiebreakers with an 0-4 record against the Ducks, Bruins and Cal.
Worst case: No. 5 seed. Arizona loses at ASU while Colorado beats Oregon State. The Wildcats and Buffs would tie at 11 wins and a split series, but Colorado has two wins over Oregon and one against Cal.

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KenPom.com predictions aren’t all that useful with such small sample sizes, but as a point of reference:
Oregon has 67% chance of winning at Utah.
UCLA has 52% chance of winning at Washington.
Arizona has 84% chance of winning vs. ASU.
Colorado has 86% chance of winning vs. Oregon St.

Here are the seeding tiebreakers, from page 57 of the Pac-12 media guide.
a. Results of head-to-head competition during the regular season.
b. Each team’s record vs. the team occupying the highest position in the final regular standings, and then continuing down through the standings until one team gains an advantage. When arriving at another group of tied teams while comparing records, use each team’s record against the collective tied teams as a group (prior to that group’s own tie-breaking procedure), rather than the performance against individual tied teams.
c. Won-lost percentage against all Division I opponents.
d. Coin toss conducted by the Commissioner or designee.