Thursday's winners will meet in Saturday's championship match at 7 p.m., also in Provo, with the champion earning an automatic bid to the NCAA Tournament.
"It is hard to say" if BYU will still get an invite to nationals if it doesn't win the league tournament, McGown said.
All four remaining MPSF teams are strong candidates to get at-large bids, and will be hoping that No. 1 Loyola (Ill.) doesn't get upset in the Midwestern Intercollegiate Volleyball Association (MIVA), because the Ramblers are definitely already in the national tournament, which they will host.
"Santa Barbara has put together a nice last half of the season, and [Pepperdine] has been great all year," McGown said. "Stanford has put together a great last half of the season. I could make a strong case for all four of the [MPSF semifinalists].
"I like my position, if I am any of us that are playing right now," McGown continued. "But like I said, we don't want to put that into the committee's hands. We want to win the conference tournament outright."
The Cougars blasted USC 3-0 in one of Saturday's quarterfinals to advance, snapping a four-match losing skid, while UCSB advanced with a 3-2 come-from-behind win over UCLA. BYU junior Josue Rivera said the blowout of the Trojans was just what the Cougars needed to regain their confidence.
"It felt good to be playing BYU volleyball again," Rivera said. "Playing well gave us fire to play even better this week."
McGown said the win changed the atmosphere in the gym "an unquantifiably large amount," but didn't give the Cougars the sense that they have solved all their early April problems.
"You can't overstate the [home] crowd factor as well," he said, looking out into the Smith Fieldhouse seats. "The amount of energy that gets poured into our team, and the amount of pressure it puts on opponents when fans are going nuts, and yelling in their ears, that's the other thing that I think is huge for us. It is just this amazing crowd energy that comes here when we play."
Sophomore Tyler Heap, who started at setter all season before severely spraining an ankle in the loss at UCLA on April 12, probably won't play on Thursday but is "possible" if the Cougars make it to Saturday, McGown said, noting that fellow sophomore Robbie Sutton started in Heap's place against USC and had a fantastic match.
Thursday's MPSF men's volleyball semifinals
P At BYU's Smith Fieldhouse, Provo
• No. 2 Pepperdine vs. No. 3 Stanford, 5 p.m.
• No. 1 BYU vs. No. 4 UC Santa Barbara, 8 p.m. (TV: BYUtv)