A hard-hitting infielder, Shipman starred for St. Louis University in 1977 and 1978. He was captain of his Billiken’s team. In 1978, Shipman had a 27-game hitting streak. He played both second base and third base for SLU. In 1975 and 1976, Shipman was a second baseman and third baseman for Concordia Junior College in Austin, Texas.

In the early 1970s, Greg played for Parkway West High School. In 1973-74, he was an infielder for the Manchester American Legion team. Shipman played for the Fenton Vets from 1975 to 1977j. He was excellent defensive player and a very good hitter. Every year, his batting average was .340 or higher. In 1979 and 1980, Shipman coached the Creve Coeur American Legion team.