Dave Henderson didn't play for the Giants in 1988. He became a free agent after the 1987 season and signed with the Oakland A's.
Mike Aldrete started in LF for much of the season. He batted .267 in 389 at bats. He had only 18 extra-base hits (.329 slugging percentage).
Jeffrey Leonard batted .256 in 44 games. He was traded to the Milwaukee Brewers on June 8 for Ernest Riles.
Joel Youngblood batted .252 in 123 at bats as a pinch hitter and extra outfielder.
