For us, our worst attended playoff games are the Thanksgiving weekend (around 14k), but then the attendance numbers improve the further into the playoffs we get. I'm guessing that we'll see about 20k this weekend, and the potential for a sellout in the quarters if we get there.
I find it ironic though how much of a difference winning/losing Cat/Griz made. For the Cats, it looks like they're pretty much sold out already (at least on their ticketing site, there are only a handful of seats left in the athletic center end zone), but they still have SRO tickets available.
Compare that to our loss, and the only loss for the season. We got the #3 seed, which is the best we could ask for and by all other metrics, that's a fantastic seeding. But it's interesting how the results of the Brawl kinda put a wet blanket on everything. Had we won that game, I think we'd see this 2nd round game against SDSU be closer to a sellout than it currently is right now. And I think the inverse is possible for the Cats had they been the ones to lose the Brawl.