Ronda Rousey vs Gina Carano or Cristiane Cyborg Justino?

Joe Rogan started a firestorm of rumors after he said on KRock FM that the UFC's making a big announcement which will bring competition for Ronda Rousey. This points directly to the UFC signing Cyborg Justino. Some think it's Gina Carano who will be stepping in to fight Rousey, but that seems quite unlike as she hasn't expressed interest in fighting and then to drop down to 145 and fight the champion right off the bat seems quite unlikely. Rousey's hero actually is Gina Carano, and she has been very respectful to Carano her whole career with her speech.