The Mets drafted Roy Staiger in the first round of the 1970 amateur draft with the 24th overall pick. He spent six seasons in the minors before making his Major League debut on September 12, 1975. As the starting 3rd baseman he went 0 for 4 as the Mets lost 5-1 to the St. Louis Cardinals. The next day he recorded his first big league hit, an 8th inning double. Overall Staiger appeared in 13 games for the Mets in 1975 and batted .158 (3 for 19).
Staiger spent the entire 1976 season with the Mets. He initially platooned with Wayne Garrett at 3rd base but when Garrett was traded in July he became the primary 3rd baseman. He appeared in 95 games and hit just .220 with 2 home runs and 26 RBIs. He was one of the Mets hottest hitters in the month of August when he hit .273 with 2 home runs and 12 RBIs. He hit his first home run on August 2 against the Montreal Expos.
He started the 1977 season with the Mets but struggled at the plate and was demoted to the minors in the beginning of June. At the time of his demotion his average was .231. Staiger returned to the Mets when rosters expanded in September. He appeared in a total of 40 games for the Mets in 1977 and batted .252 with 2 home runs and 11 RBIs.
Following the season, the Mets traded Staiger to the New York Yankees in exchange for Sergio Ferrer, it was the first trade ever between the two teams.
In 148 game Staiger hit .226 with 4 home runs and 37 RBIs.
While with the Mets Staiger wore number 35 in 1975 and number 2 in 1976 and 77.
Roy Staiger also played for the New York Yankees in 1979.