The Hawaii volleyball team enters the must-sweep stage of the season, with road matches against Cal State Northridge tonight and Saturday.

UC Irvine (14-3), UCLA (13-3), Brigham Young (13-3) and Southern California (12-4) have clinched berths in the Mountain Pacific Sports Federation’s eight-team postseason. Stanford (11-4) and Pepperdine (7-9) are in favorable positions to earn spots.

“The top five teams certainly are above everybody else in terms of win totals,” Northridge coach Jeff Campbell said.

The separation opens the way for Hawaii, which is 10th in the MPSF with a 4-12 league record, to contend for a postseason berth with six regular-season matches remaining.

Long Beach State (5-9), Northridge (4-10), Pacific (4-11), Hawaii, UC San Diego (4-13) and UC Santa Barbara (3-13) are in a cluster.

The Warriors close their regular season with two matches each against Northridge, Long Beach State and UC Santa Barbara.

“They’re all important matches, but (this weekend’s) matches are really critical at this point of the season in terms of the standings,” UH associate head coach Jeff Hall said. “We’re trying to make a push for the playoffs. We’re looking forward to the challenge.”

The Warriors received a recent boost with the return of middle blocker Shane Welch, who has recovered from knee surgery.

Welch’s long reach is an obstacle for opposing attackers. Welch and Jarrod Lofy, a senior, have split time at that middle position. Nick West is the other starting middle.

The Warriors appear to have found a workable solution at opposite attacker. Taylor Averill, who is 6 feet 7, plays in the first five rotation turns before yielding to 6-1 Harrison Carroll. Later in the set, Averill will return.

The platoon plays to both players’ skills. Averill is an active blocker and powerful front-right hitter.

Carroll is better hitting D sets from the back right, as well as a solid back-row defender.

“We’ll go with this until something goes terribly wrong or somebody really establishes himself as the full-time guy,” Hall said.

The Matadors also have been scrambling for answers after their best outside hitter, Matt Stork, suffered a stress fracture in his leg. He has missed the past two weeks, and his return won’t be projected until after he is examined in another week.

“It certainly has hampered us in terms of not having a go-to guy,” Campbell said. “He had three years of experience playing on this team. That was really important. We don’t have anybody else like that right now.”