In 1984, the Padres reached the World Series for the first time in franchise history. McReynolds along with rookie outfielder Carmelo Martínez was hyped as the M&M Boys after the New York Yankees 1960s power-hitting duo of Mickey Mantle and Roger Maris. McReynolds shared the team lead for home runs with 20 and Martinez was fourth on the team with 66 RBIs. During the 1984 National League Championship Series (NLCS) McReynolds had a .300 batting average, hit 1 home run and 4 RBIs. However, he broke his wrist trying to break up a double play in Game 4, and was out for the season. The Padres won Game 5 and advanced to the World Series, losing 4–1 to the Detroit Tigers.