Jack Quinn was somewhat of late bloomer when he made his major league debut with the New York Highlanders. He was 25, which is far from old, even in 1900s baseball. However, more than 50 other rookie pitchers who played in the 1909 season were younger than him.
Despite that, Quinn stuck around quite a while. He played four seasons with the Highlanders, then had a couple years in Brooklyn and Baltimore. After totally missing two major league season, Quinn played for the White Sox, a couple more years for the now Yankees, and then had some time with the Red Sox.