Tyler Alan O'Neill (born June 22, 1995) is a Canadian professional baseball left fielder for the St. Louis Cardinals of Major League Baseball (MLB). He made his MLB debut on April 19, 2018. He has represented Canada in international play, winning a gold medal at the 2015 Pan American games. O'Neill stands 5 feet 11 inches (1.80 m) tall, weighs 210 pounds (95 kg), and throws and bats right-handed.