Paul F. Hartzell is an American former professional baseball pitcher, who played in Major League Baseball (MLB) in all or part of six seasons, between 1976 and 1984. During that time, he pitched for the California Angels, Minnesota Twins, Baltimore Orioles, and Milwaukee Brewers of the American League (AL). Hartzell retired in July 1981, but returned to baseball in 1984, playing at each level of professional baseball in one season, culminating with his first MLB appearance since June 14, 1980, when he appeared in relief for the Brewers on September 15, 1984. He was known as a ground-ball pitcher.