Clifford Douglas Blankenship (April 10, 1880 – April 26, 1956) was an American professional baseball player. He played his first game on April 17, 1905. He played his 95th and final game on August 18, 1909. His batting average was .225. In 1907, Senators manager Joe Cantillon sent Blankenship to Weiser, Idaho, to scout pitcher Walter Johnson. Blankenship successfully persuaded Johnson to accept a Washington contract.