He posted a 9–2 win–loss record as a pitcher in his freshman year,[1] and threw the school's first no-hitter, a 4–0 victory over Dartmouth at Fitton Field in 1918.

[1] Ryan went 15–8 with a 1.36 earned run average (ERA) for the Buffalo Bisons of the International League in 1919, and was called up by the New York Giants late in that season.

He made his major league debut on September 7, getting the start on the mound in the second game of a doubleheader against the Boston Braves at the Polo Grounds.

The game featured a pair of Baseball Hall of Famers at shortstop in Boston's Rabbit Maranville and the Giants' Frankie Frisch.

[4] Despite his solid regular season performance, Ryan did not appear in the postseason as the Giants went on to claim the 1921 World Series over the New York Yankees and slugger Babe Ruth.

The Giants finally got to Yankee starter Bullet Joe Bush in the eighth, rallying for three runs and riding Ryan in the ninth for the 3–2 win.

He proceeded to walk Joe Dugan to force across a third Yankee run, but then with the bases still loaded, he fanned the mighty Ruth.

He tossed 4.2 innings of middle relief and allowed two earned runs in New York's 6–4 Game 3 win, but his moment of glory came at the plate, as he belted a fourth-inning homer to deep right field off Senators' hurler Allen Russell.