Complex sentence: Gaston is the only Blue Jays manager to win a World Series in 1992 and 1993, the fourth African-American manager in MLB history, and was the first African-American manager to win a World Series.
Split into simpler sentences: Gaston is the only Blue Jays manager to win a World Series in 1992 and 1993. Gaston was also the fourth African-American manager in MLB history, was the first African-American manager to win a World Series.