Starting out as a pitcher, Yeager went 12-22 for Brooklyn in his first season and was used sparingly the next two years as a pitcher and a shortstop. He then jumped to the new American League. Detroit initially used him as a pitcher; he went 12-11, 2.61 in 1901, but dropped to 6-12, 4.82 in 1902. The Tigers made him their regular third baseman in 1903; he hit .256 and fielded adequately, ending his pitching career. Reappearing with the Highlanders (later the Yankees) in 1905, he played 90 games at 3B and 21 at SS, batting .267, and he was a utility man in 1906, hitting a career-high .301. He played in the most games of his career with the 1907 Browns, chiefly at third, but was hampered by a hand injury and hit just .239. An illness ended his career the following season. He is credited by some with originating the squeeze play.