Mayberry was a slugging first baseman who topped 20 HR eight times (30 twice) and 100 RBI three times, and led the AL in walks in 1973 (122) and 1975 (119). He hit three homers in a game twice (7/1/1975 vs. Rangers, 6/1/1977 vs. Blue Jays) and hit for the cycle on August 5, 1977. TSN named him AL all-star first baseman in 1973 and 1975.
Mayberry showed power in four trials with the Astros but never hit higher than .216 for them and was traded to the Royals for 1972. Kansas City made him its regular first baseman, and he responded by hitting a career-high .298 with 25 HR, 100 RBI (second in the AL), and a league-leading 122 walks. A pulled hamstring in July and a broken wrist in August accounted for his mediocre 1974 performance (.234, 22 HR, 69 RBI). His best season came in 1975, when he hit .291 and reached career highs with 34 HR (third in the AL) and 106 RBI (second). He was considered one of the AL’s most feared sluggers, and other teams began shifting their defenses to the right to counter his powerful pull hitting. He slumped to .232 with 13 HR in 1976, but did drive in 95 runs as the Royals won their first division title. He homered in the last game of the LCS as the Royals lost to the Yankees.
He hit .230 in 1977, although he did have 23 HR. He also made himself unpopular in Kansas City by sitting out the last game of the LCS with a toothache as the Royals lost to New York again (he homered in Game One). Kansas City then sold the man who stood as the club’s career leader in HR and RBI to the year-old Blue Jays. He led Toronto in RBI and HR each of his four seasons there, rebounding to 30 in 1980 and setting since-broken HR and RBI career marks for the young franchise, but he never totally regained his former productivity. Three times he had the Blue Jays’ only hit in a game. Traded to the Yankees in May 1982 for two prospects, he slumped abysmally, batting only .209 for his new team, and his career ended.
Mayberry is the Royals’ season record holder in walks (122) and double plays by a first baseman (156) and still ranks in their top ten in most career offensive categories. Although the 6’3″ 220-lb Mayberry was a very slow runner, he was quite agile around the bag and led AL first basemen three times in putouts, twice in fielding, and twice in double plays.