Is Collier from Houston?
Wouldn't shock me if he ran for Mayor in 2015, which would position him for statewide office again in 2018.
He lives in Kingwood, which is the random exurban appendage of Houston that the city annexed in the '90s and that most people forget is even part of the city. He can't launch a mayoral bid from there because he'll have no base of support. Houston politicians ignore Kingwood because it's so far away from the rest of the city and it's hardcore Republican. So Collier's own neighborhood won't support him because he's a Democrat and the core neighborhoods won't support him because he's not from there.