If you look at his whole bracket, ISU is the lowest seeded of 6 Big 12 teams. I don't believe the conference will get 6 teams in this year. It is just not that strong. Plus, conferences like the Mountain West are doing well this year. It's possible that conference will get in 4 teams, maybe even 5.
However, I also don't see Baylor and OSU finishing ahead of ISU in the Big 12, from what I have seen of them so far this year. ISU has to figure out a way to better contend with other team's bigs, but if they can do that......I think they can finish no lower than 4th in the conference, and maybe get as high as an 8 seed.
plenty of other weak leagues as well: SEC, ACC, and BigEast might "only" get 7. plenty of spots available - big 12 is going to get more teams in than many think (although seeds might be crappy).