"The men's basketball program has made seven NCAA appearances since 2000, the women's basketball program has advanced to three NCAA Final Fours and football went to a bowl game last season in just its fourth year in the BCS."
The Golden Hurricane, who joined C-USA in 2005 after leaving the WAC, won last year's football championship in the league and recently won the women's basketball tournament title while hosting both hoops tourneys.
Last week, Tulsa hired Derrick Gragg as its new athletic director. He replaces Ross Parmley, who was fired amid gambling allegations.
Conference USA will have 14 football teams for the 2013 season, even with current teams SMU, Houston, UCF and Memphis leaving in three months. Tulane and East Carolina have previously announced they'd be leaving in 2014, the same time as Tulsa.
Sun Belt Commissioner Karl Benson said Western Kentucky's decision "is not a surprise given the communication that I have had with university officials and the rampant speculation over the past several months."
Benson said he has long understood the implications of the move and that the Sun Belt has been preparing for this possibility for quite some time.
The Sun Belt last week added Appalachian State and Georgia Southern as all sports members and Idaho and New Mexico State as football-only members.
Petrino was hired in December as Western Kentucky's new football coach. That came nine months after he was fired by Arkansas following an accident in which the coach was injured while riding a motorcycle with his mistress - and newly hired football program employee - as a passenger.
Petrino took over at WKU for Willie Taggart, who left to become South Florida's coach. Western Kentucky gave Petrino a four-year deal.