USC, which finished in a three-way tie for eighth place in the Pac-10, will play in the first game of the conference tournament Thursday night in Tucson. The Trojans will play Cal, which also finished in that tie for eighth place along with Washington.
UCLA's first game of the tournament will be Friday night against Washington State.
UCLA finished the season tied for second place with Oregon State. But Oregon State was seeded second and UCLA third because Oregon State swept the Bruins in regular-season play.
USC got the highest seed of the teams tied for eighth because of its 3-1 record against Cal and Washington. And Cal was seeded higher than Washington because it swept their series.
Top-seeded Arizona will meet UCLA only if the Bruins and the Wildcats advance to the final game. Winning the tournament means an automatic berth in the National Collegiate Athletic Assn. tournament.