Yeah, it was quite possible and a big fear of the US. Some speculate that it was one of the reasons the US dropped the bombs. The USSR was getting ready for an invasion of Hokkaido and was somewhat disappointed the war didn't last long enough for it to actually get a bigger piece of Japan. If you ask some Japanese, they'd say that it was divided with Sakhalin and the Kuril Islands going permanently to Russia.
A divided Japan was a big fear for the US and its allies and a major worry for Japan, as well, especially considering how China and Korea went.
Thanks,
Logan