Simplify the following text for a Grade 10 native English-speaking person.
Original: Robinson thus simultaneously became the first black player to openly play for a minor league team and against a major league team since the de facto baseball color line had been implemented in the 1880s .
Simplified: With the game Robinson became the first African-American to openly play for a minor league team and against a major league team since the baseball color line had been put in place in the 1880s .