"I just went out and played the game, that's all," Mayberry said.
He played it well, one of the legion of young African-American players who followed the lead of Jackie Robinson, the trailblazer who will be honored throughout Major League Baseball on Sunday.
"I always grateful to Jackie Robinson for all that he had to go through. I was one of the beneficiaries and I was appreciative of that," Mayberry said. "And of course, when I came up, there were a lot of blacks in baseball. I played on teams that there were four or five or six black guys starting and some on the bench. So I had a real good time, a lot of camaraderie, a lot of fun -- all because Branch Rickey gave Jackie Robinson his chance and broke the color barrier, and Jackie represented us well."
Mayberry was born in 1949, two years after Robinson broke the color barrier, and grew up in Detroit as the son of an auto factory worker. Even when Big John was little, he was outgoing and full of spirit and fun.
"I think that came when I grew up with six brothers. We all used to get on each other and fight with each other and just played baseball all day," Mayberry said. "We created our own games and rules and had our heroes like Al Kaline and Rocky Colavito and all these guys. Willie Horton came along, and Gates Brown. I tell you, we used to fight about how many strikes and how many outs and everything else, but we just loved the game from sunup to sundown."
Mayberry played it so well that he was drafted in the 1967's first round by the Houston Astros. Maybe it was the Ted Williams influence.
2012 Jackie Robinson Day coverage
"Ted Williams was one of my biggest idols in baseball. I didn't read many books but I read his book, 'My Turn at Bat.' That's the most fascinating book I ever read in my life. He wanted to be a great hitter, and I did, too," he said.
Big John couldn't crack the big league lineup at Houston, but his hitting for Triple-A Oklahoma City caught the attention of Jack McKeon, who was managing Omaha for the Royals. Apparently Kansas City general manager Cedric Tallis listened, because in the winter of 1971, he swung a trade for Mayberry who reported the next spring to manager Bob Lemon.
"He was an old timer, and he had a lot of patience. He told me the first day of Spring Training, 'Son, the job is yours until you prove you can't play.' And after five or six years in the Minors, that's all you want to hear," Mayberry said.
In each of his first two years with the Royals, Mayberry drove in 100 runs with 25 home runs in 1972 and 26 in 1973. His most productive season was '75, when he hit 34 homers, 38 doubles and had 106 RBIs with a .291 average.
"I played in a big ballpark, one of the biggest in baseball, and it was kind of frustrating for a power hitter," he said.
He changed his hitting style at Royals Stadium, knowing he probably wouldn't get many opposite-field home runs so he became more pull conscious.
In fact, to Mayberry went the distinction of hitting the first home run at what is now called Kauffman Stadium on April 10, 1973. It hit the back wall of the right-field bullpen. (Mayberry also hit the Royals' last home run at old Municipal Stadium, on Sept. 29, 1972.)
Mayberry, dealt to the Toronto Blue Jays before the 1978 season, put in 15 seasons in the Majors, from 1968-80.
"My whole thing when I was about 11 or 12, I just wanted to be half as good as Willie McCovey, just as half as good as this big dude. And, lo and behold, I was about half, because I hit 255 home runs and he hit 520-something. So I kind of predicted that," Mayberry said, with a mighty laugh.
His son, John Mayberry Jr., is playing outfield and first base for the Philadelphia Phillies, carrying on both the family tradition and the Jackie Robinson tradition.
"Jackie went through some very difficult times, and what impressed me is he blotted that out and played the game at a high level," the elder Mayberry said. "A lot of times, he could've gotten down and said, 'Oh, forget about this, I can't go through all this to play baseball. I'll just go back to the Negro Leagues.' But he said, 'No, I'm going to give it the best that I can. I can play for anybody in the world.' I think he had that type of attitude, that kind of determination that you don't put into somebody. It's got to already be there."
Mayberry grew up hearing the Robinson stories and knowing he was a great player.
"But then I started seeing better players that came along in the Majors Leagues. I'm talking about guys like Frank Robinson, Hank Aaron, Willie Mays, Willie McCovey and Ernie Banks, and those kind of guys," he said. "I give Jackie Robinson all the respect but these guys I actually saw and they were really at a high level. They were pretty inspirational to my generation and in my career."