Can you leave sourdough pizza dough out overnight?

This depends on the ambient temperature, and the type of dough you are using, but as a rule you should keep it chilled overnight, or it will likely over-prove. The ideal method is to thaw in a sealed container overnight (or up to 3 days) in the fridge and then remove in time to reach room temperature before you want to cook. If you have forgotten to thaw overnight in this way, it is still possible to thaw and prove at ambient temperature, this will take around 6-12 hours depending on how warm the area is and which dough you are using.