Ayala made his major league debut as the Mets' starting left fielder at Shea Stadium on August 27, 1974. With one out and the bases empty, he hit a home run in his first at bat off the Houston Astros' Tom Griffin to open a three-run rally in the bottom of the second inning in a 4–2 Mets victory. Wearing uniform number 18 and strictly a corner outfielder, Ayala played in only 45 games with the Mets (23 in , 22 in ).