The tennis ace has kept his thoughts about the referendum to himself - but he revealed he has been following the build-up and watched 45 minutes of the second debate between Alex Salmond and Alistair Darling.
"If Scotland became independent, I imagine I would be playing for Scotland," he said in New York after qualifying for the US Open third round.
"I have not thought that much about that yet because I do not think it is looking too likely that it is going to happen. But if it did happen, then it would be pretty much the first time in my life that I would have ever (had the chance to play for Scotland).
"Since I started travelling to tournaments when I was 11, I have played under Great Britain. That is normal to me."