To start the 1972 season, Stein was a member of the Triple-A Tulsa Oilers. With Tulsa that year, he batted .278 with 100 hits, 26 doubles, four triples, five home runs, and 36 RBIs in 103 games played. Stein was a September call-up for the St. Louis cardinals that year. He made his debut in Major League Baseball (MLB) on September 6, 1972, against the Philadelphia Phillies. He got his first hit in that game, which was a home run in the ninth inning. He played 14 games in the majors that year, batting .314 with two runs scored, 11 hits, one triple, two home runs, and three RBIs. Defensively in the majors, he was positioned at third base, left field, and right field.