Elmer Jay Rieger (February 25, 1889 – October 21, 1959), was a Major League Baseball pitcher who played in 1910 with the St. Louis Cardinals.

He batted right and left and threw right-handed.

Rieger had a 0–2 record, with a 5.48 ERA, in 13 games, in his one-year career.

He was born in Perris, California and died in Los Angeles, California.

This biographical article relating to an American baseball pitcher born in the 1880s is a stub.