On November 23, 2010, Martínez and the Tigers organization reached an agreement on a four-year, $50 million free agent contract. On March 31, 2011, Martínez made his debut for the Tigers as a designated hitter against the New York Yankees. Martínez was used almost exclusively as a designated hitter for the 2011 season, playing only 26 games at catcher and 6 games at first base. He had a slow start to the season, batting .250 in the month of April with two home runs, but he then batted .337 in May and .370 in June. On September 11, in a game at home against the Twins, he had perhaps his worst-ever game at the plate, going 0 for 4 and hitting into four double plays (three of them GIDPs, one a line drive); his team managed to win anyway, 2-1. It was the first time a batter had hit into four double plays in the American League since hall of famer Goose Goslin did so in 1934, also while playing for the Tigers, and also in a game the Tigers won, 4-1. Although his power numbers were down, with only 12 home runs all season, Martínez posted his best career batting average (.330, good for fourth best in the American League), tied his career high with 40 doubles, and had his fourth career 100+ RBI season (103). He also led the Major Leagues in batting average with runners in scoring position, hitting .394.