Can't find a lot of information as to how Greg Smith came to be on card number 151 of the 1987 ProCards set in an Oklahoma City Eighty-Niners uniform.
I can find records that indicate that the career minor leaguer began his pro ball career with the Dodgers Rookie Ball team in 1980. In four seasons in the Dodgers' system he never made it above Double A ball. In fact, he had trouble sticking in Double A.
In 1984 Smith moved to the Padres' system. Not sure what the circumstances were of the move but since it happened mid-season I would figure it was a trade. Greg finally made it to Triple A in 1986 with the Padres' Las Vegas affiliate.
In 1987 he played for Oklahoma City in the Rangers' system. Again, no idea as to how the move came about. Perhaps it was a minor league free agency signing or maybe an off-season trade. Whatever the reason for the move and however it came about it would be the last for Greg Smith. After the 1987 season he was out of professional baseball at 27 years old with eight minor league seasons under his belt.