Dennis Kay Aust (born November 25, 1940) is a former Major League Baseball pitcher. Aust played for the St. Louis Cardinals in 1965 and 1966. He batted and threw right-handed.Aust was signed by the Cardinals as an amateur free agent in 1961.Aust's only decision came on the Cardinal's opening day in 1966 when he pitched 3 innings in relief. After getting the first two batters out in the top of the 12th inning, he surrendered a hit to Dick Allen followed by an intentional walk to Bill White.