After spending three seasons in their minor league system Kelvin Chapman earned his way on to the Major League roster following a phenomenal spring training in 1979. He made his debut as the Mets starting second baseman. He got his career off to a fast start, singling in his first at-bat, and hitting safely in his first three games. But than his bat went cold and with his average at just .150 he was demoted to the minors in the middle of May. Chapman spent the remainder of the season in triple-A before returning to the big club as a September call-up.
Chapman spent the next four seasons playing exclusively for the Tidewater Tides, the Mets top minor league club. He finally returned to big club in 1984 serving as a part-time player and pinch hitter and put up decent numbers, hitting .289 with 3 home runs and 23 RBIs. Chapman returned to Mets in 1985 but once again struggled at the plate and was demoted back to the minors halfway through the season with his average at just .174.
The Mets released Chapman following the 1985 season ending his pro baseball career. Chapman appeared in a total of 172 games for the Mets and hit .223 with 3 home runs and 34 RBIs.
While with the Mets Chapman wore number 10 in 1979 and number 11 in 1984 and 1985.