I know someone else whose DS went through a phase like this at about this age-- eventually Mom made a rule that baseball could only be discussed at certain times of the day, or for a set amount of time at once.

This child is HG+ and also well-rounded otherwise-- highly musically gifted, good at academics, but occasionally obsessive about an interest. For a while it was baseball. smile

Schrödinger's cat walks into a bar. And doesn't.