Harrelson has broadcast for the Boston Red Sox, New York Yankees and Chicago White Sox, spending 27 years in Chicago. Shannon has called St. Louis Cardinals games for 42 years following a nine-year playing career with the Redbirds.
Other finalists for the Ford C. Frick Award are: Joe Castiglione, Jacques Doucet, Bill King, Duane Kuiper, Eric Nadel, Eduardo Ortega, Dewayne Staats and Pete van Wieren. Doucet, King and Kuiper were the top three picks in online voting by fans.
Final voting for the award, presented annually for excellence in baseball broadcasting, will be conducted by a 20-member panel. The winner will be announced on Dec. 11 at the baseball winter meetings.