Could Stalin attack Hitler in an alternate 1942?

Could the European war instead begin with Stalin attacking Hitler in 1942?

Potentially, but Soviet forces would have to get through Poland, so Poland's fate is the decisive condition.

The European war might begin in the east, with Stalin attacking Hitler in 1942 rather than the western Allies confronting Germany. The idea is possible, but Poland remains the geographic and political barrier between the two powers. Soviet forces would need a route through Polish territory, and that depends on Poland's fate after the 1939 crisis. Alliance history and military access are the main constraints on the counterfactual.