So every summer, when school let out in Lexington, Ky. -- and even, sometimes, a little before that -- John, his mom, Trina, and his brothers would pack up their suitcases and join Shelby Jr. wherever he was working.
"We were batboys in Butte, Bakersfield, San Antonio and Savannah," recalled the younger Shelby. "San Antonio was something I remember in particular because we had our first Kentucky game at that same field."
Those experiences have probably prepared him better for his immediate future than his summers at Chavez Ravine did.
There has never been a time when Shelby didn't know exactly what he wanted to be when he grew up.
"I can't remember one day when I didn't wake up with baseball on my mind," said Shelby, the oldest of six kids who all grew up in Lexington. "Playing professionally has always been a dream of mine."
Since the elder Shelby transitioned right from playing into coaching and managing, he rarely got the luxury of seeing any of his sons play organized baseball.
"He's probably only seen me play a handful of times," Shelby said. "It seemed like every time he got a chance to come home, we would be rained out."
Instead, Trina Shelby relayed most of the postgame play-by-play to her husband by telephone, and he'd pass along his advice.
This is not to say the elder Shelby didn't get a chance to work hands-on with his sons (younger brothers Jeremy and Justin are also up-and-coming players).
"Wherever we went, he'd take us out to the cage and give us tips," Shelby said. "But he never forced us to do anything. He'd let us be ourselves."
Though his dad made his mark as an outfielder, the 5-foot-11, 185-pound Shelby has embraced the middle infield, playing shortstop as a child and now having shifted over to second base.
"In Little League, they put the people who loved the game at shortstop," he said. "I always had a passion for playing middle infield because you're involved in more plays."
After all that summer travel as a child, when it came time for college, Shelby chose his hometown school, the University of Kentucky.
This year, the Wildcats are having an unprecedented season, as Shelby, in all likelihood, winds up his college career in grand style as the second baseman of one of the top teams in the country.
It's a position that also seems to fit his strengths: speed, agility and soft hands.
Timed at a fine 4.0 seconds to first base, Shelby knows his quickness will be one of his selling points in next month's First-Year Player Draft.
"You can't teach speed, so that's definitely a tool that I think will enhance my draft status," he said.
A line-drive hitter with gap power to the opposite field, perhaps his best asset, not surprisingly, are his unerring baseball instincts.
These are all tools that are likely to prompt Shelby's name to be called within the first five rounds of the draft, but for now, he's not focused on that.
Not with the Wildcats coming off clinching the SEC Eastern Division title over the weekend to put them one win away from what would be the school's first outright conference championship.
At 40-11, the Wildcats find themselves with the No. 4 ranking in Collegiate Baseball's Top 25, behind perennial powers Rice, Cal State Fullerton and the defending College World Series champion Texas Longhorns. They're also riding an eight-game winning streak and are one victory away from a school record for wins.
So it doesn't sound coy at all when Shelby says of the draft, "I honestly haven't even thought about it. Right now, I'm totally focused on the college season. Everything else will fall into place."