... the backup plan if BYU says no. If the Big 12 is ultimately going to 12 teams, with BYU and Notre Dame in the Big 12 North, you'd need a team in the south to back it up.

The void left in the Houston TV and recruiting market by the departure of A&M could be somewhat offset by bringing in UH and having 6 annual Big 12 games played in the city every year.

It's not so much about UH's market penetration as it is UH playing 6 home games against Big 12 teams in the city. That makes them a viable candidate and the likely 3rd team (assuming the Big 12 can't get Arkansas, their preferred southern division choice).