Yamada Takayuki is in both of the drama's as the main character, while H2 were about Baseball team, Water Boys were dealing of the problem in Men sychro team.
Both is about baseball, but if rookies is more transforming delinquent into a baseball champion, H2 is more into 2 bestfriend that approaching their dreams to become a star player of baseball by entering a drifferent school, 1 of them go to school that strong in baseball and the other don't.