Complex sentence: Selected for the 1991 All-Star Game, Henderson was on the way to the best season of his career as batting in the number-two spot in the A's lineup behind Rickey Henderson seemed to have a great effect.
Split into simpler sentences: Selected for the 1991 All-Star Game, Henderson was on the way of the best season of his career. Batting in the number-two spot behind Rickey Henderson seemed to have a great effect.