Simplify the following text for a Grade 14 native English-speaking person.
Original: Robinson 's career is generally considered to mark the beginning of the postâ `` `` long ball '' era in baseball , in which a reliance on raw power-hitting gave way to balanced offensive strategies that used footspeed to create runs through aggressive baserunning .
Simplified: Robinson 's career is generally considered to mark the beginning of the postâ `` `` long ball '' era in baseball , in which a need for power-hitting was replaced with balanced offensive strategies that used footspeed to create runs through baserunning .