I think we see the trilogy or Froch retiring if he loses. I'd be surprised if a big American fight would be likely on the back of a defeat against Groves especially after the nature of his win in the first fight and the reaction after it. He'd need at least one more fight before he'd get a Chavez Jr. or Golovkin fight and I'm not sure he'd go for that considering how he's spoke about needing big fights to motivate him. Interesting thing if he gets beat is whether he fancies another go at Groves who clearly gets under his skin. Pride would be a motivating factor to not let Groves retire him but could he take a loss in a third fight that would truly leave him with no options?
There won't be much point going to Vegas for Chavez if he loses. Froch coming off a loss to Groves and Chavez off one to GGG - not exactly something which will get HBO chucking their money around.