And so, he'll be there with his mom, Alicia, who he calls the family's "backbone," his sister Anisha, an accomplished singer who will offer the U.S. and Canadian national anthems before the 1:30 p.m. ET ceremony, and about 50,000 of their closest and most intimate fans and friends.
But it will be Tony, the father, that his son will be there to honor as much as Tony, the player.
"I love my dad for stuff he did off the field more than he did on the field," Little Tony said. "When I was little and I picked a favorite player, it wasn't going to be my dad. I didn't want to pick my dad because that was my dad. I wanted to go a different route."
At 7 years old, he picked Will Clark and said so in an interview done by the Hall of Fame for a short film honoring his dad.
Asked expectantly to talk about who he wanted to emulate as a hitter, he said "To be honest with you? I was trying to be like Will Clark."
Back in May when Gwynn Sr. saw the outtake during his initial walk through the museum, he broke into a belly laugh.
"We knew what was coming," said Gwynn, who mused that he turned his son into a Clark fan by edging the then Giants first baseman for the National League batting title on the last day of the 1989 season.
Not so, says the son.
"I just liked the way he swung the bat," Little Tony said about Clark, who like the Gwynn father-son tandem was a left-handed hitter. "I loved his stance. That was my favorite part about it. And it seemed like there was very little effort to his swing. Something about him just attracted him to me."
For those who know the Gwynn family, it may come as no surprise. The father taught his son to be independent and not to fall under the shadow of his famous ballplaying father, who ultimately won eight NL batting titles and sprayed 3,141 hits during his 20-year career, all with the Padres.
Gwynn Sr. still is idolized in San Diego, where he went to college at San Diego State, is now the school's head baseball coach and continues to reside there in North San Diego County.
When it comes to listening to the 24-year-old, his verbal intonations are much like his father's and his laugh -- more like a cackle -- is a dead ringer.
"We'll you better get used to it," Little Tony said with that unmistakable chuckle. "I am his son."
Gwynn Jr., plays the outfield like his father and uses the same sized bat: 33 ounces.
But the one thing he won't do is don his father's famous No. 19, which is one of only four numbers retired by the Padres.
"I don't want anything to do with that," said Little Tony, who wears No. 22 when he's with the Brewers because that's the number they gave him. "He can keep it."
His dad, now 47, told his son from the get-go to be his own man.
"That's the way I try to look at it," Little Tony said, "especially when you have the same name. That plays the biggest part in it. When you have the same name, guys tend to want shy away from that. I thought my dad was great, so I'm always willing to talk about what he did. But I'm going to be me, regardless. No matter what he did, I still have to wake up and be Tony Gwynn Jr. all the time. And I'm never going to change. I came to that understanding early, early before I could even comprehend what was going on."
If not for that mind-set, the expectations could be crushing. Anthony Keith Gwynn was a .338 lifetime hitter. Anthony Keith Gwynn Jr. is a .268 hitter in parts of two seasons with the Brewers, who have yet to make a commitment to him because manager Ned Yost has wondered openly if he'll be able to hit with any consistency in the Major Leagues.
Little Tony struck out in four successive at bats last weekend during a three-game series against the Giants and was optioned again to the Minors on Wednesday when center fielder Bill Hall came off the disabled list. The younger Gwynn has already whiffed 39 times in 190 big-league at-bats. His Hall of Fame father struck out only 434 times in 9,288 at bats -- an astounding average of just 21.7 a season.
How do you live up to that? The answer is, you don't.
Little Tony said his dad never pressured him into a baseball career.
"He stayed so far away from me when I was a kid, especially on the baseball field. He was a lot more demanding on the basketball court," Little Tony said, speaking about his father's first love, a sport Gwynn Sr. excelled in along with baseball at San Diego State. "I don't know if it was on purpose, whether he didn't want to push me away from the game, but he didn't say anything until I became serious about it. And I had to start asking questions. I had to go to him. That opened the box up. It was like a pool of information."
Little Tony went on to play one year for his dad, of course, at San Diego State, after Tony Sr. retired from the Padres in 2001.
"That was some of the best moments I had," Gwynn Jr. said.
Another big moment will certainly be Sunday, when his dad approaches the podium, has the inscription on his plaque read by Commissioner Bud Selig and addresses the expectant crowd. The elder Gwynn has said that he hopes to keep his emotions in check. The younger one will be measuring that barometer, too.
"He'll be like a kid in candy store," Little Tony said. "He loves that stuff. Now he's part of all that history that's in there. It's going to be a special day."