He made his major league debut on April 10, pitching a scoreless eighth inning in the Mets second game of the season, a 3–2 11-inning loss to the Philadelphia Phillies at Shea Stadium.

[3] In his next appearance, against the Chicago Cubs, Baldwin replaced Randy Tate in the seventh inning with runners on second and third and nobody out.

He induced a weak fly ball, then struck out the next two batters to escape the inning without allowing a runner to score.

Baldwin also began the 1977 season in Tidewater, but was called up to the majors after the Mets released Ray Sadecki in early May.

Baldwin's final major league appearance came on October 2, 1977, when he faced two batters in the ninth inning, earning a save in a 6–4 Met win over the St. Louis Cardinals at Busch Memorial Stadium.