It was footage about 20 years old, taken when Pena Sr. was the Pirates catcher and a Major League veteran. Before heading down to the ballpark, Pena Sr. was pitching to five-year-old Tony in the backyard. The little boy couldn't stop smiling, hitting the ball with a Wiffle bat and running around.
The videotape was a reminder of a lesson that Pena Sr. had told Tony and his brother, Fernando, for many years.
"He said, 'You just have to stop thinking about everything and go out there and have fun,'" Pena Jr. recalled. "Just go out there, have the most fun you can and play like you were a little kid. ... I try to remember that always."
It's a lesson that Pena takes to the Major League diamond on a daily basis, never forgetting his father's words. Currently the starting shortstop for the Royals, Pena Jr. is in his first full year of Major League Baseball, displaying a strong glove at shortstop and hitting well as Kansas City's No. 9 hitter.
These days, he comes to the park every day with a smile -- a smile that shows a player who is happy, a player who has been around the game since he was little and a player who has always looked to his father -- his hero -- for advice on being both a better ballplayer and a better person.
"We talk about everything," Pena, Jr. said. "We definitely talk about me more. He has kind of been my psychologist. He just tells me to go out and not think about a lot of what is going on. That's the No. 1 thing -- just to keep it simple, and have fun."
It's been that way for as long as Tony Jr. can remember. From early on, Pena Sr., who has served as the Royals manager and is currently the New York Yankees first-base coach, immersed his sons -- Tony Jr. and Fernando, 17, currently a catcher in the Mets system -- in baseball.
"I think their passion for baseball came from being around the house," Pena Sr. said. "The only thing they saw at home was baseball, baseball, baseball. There was home, stadium, home, stadium."
For Pena Jr., it was a life perpetually spent in big-league ballparks. He never played organized ball, summer baseball or American Legion baseball. He never played in a league and never faced a pitcher his own age.
Instead, Pena Jr. spent his summers with his father, traveling from city to city, where he would take ground balls before games and play with other players' children. He remembers his dad loving the game and displaying a perpetual smile. More than anything, he remembers his father playing the game like a kid.
"I had a lot of good childhood memories," Pena Jr. said.
It was a unique developmental process for the sons. While other children received instruction on youth baseball diamonds from coaches and camp instructors, the Penas enjoyed lessons from Major Leaguers.
"They grew up in the clubhouse, they grew up around players and they grew up around big-league fields," Pena Sr. said. "I think because they saw it so much, it became part of their lives, and they said they can do it because it's the only thing they knew."
Pena Jr. received advice not only from his dad, but from some of the greatest shortstops the game has ever seen. There was acrobatic Ozzie Smith in St. Louis and the graceful Omar Vizquel with the Indians: Pena Jr. watched Vizquel every day, fielding grounders, throwing to first and turning the double play.
"I wanted to do that," Pena Jr. said.
When he was 17, he received his chance, signing his first professional contract after attending a scouting showcase. Pena Jr. had an offer to play baseball at a junior college -- an offer that his dad wanted him to take -- but he wanted to play professional baseball. With a difficult decision to make, he told his father he would be signing the contract. Pena Sr. understood.
"I wanted to be happy," Pena Jr. said. "Playing baseball was going to make me happy."
Pena Jr. rose through the Minor Leagues and eventually made it to the Majors, picking up 44 at-bats with the Atlanta Braves in 2006. He was traded at the end of Spring Training to the Royals and has started nearly every game this season. He has emerged as a fine defensive shortstop, and despite his lack of professional hitting experience, he has emerged as a solid hitter, recently compiling the longest hitting streak of any Royals player this season.
His brother, Fernando, plays for the Class A Savannah Sand Gnats.
"Every time I see a game, I'm just happy to see them play and happy to see their performances," Pena Sr. said. "At the same time, you get nervous. I tell you what, it's a great feeling. In the past, I heard people talking about the fathers and sons who played in the big leagues and I thought it wasn't a big deal. Now, to me, it's a big, big deal, just watching them do what I did."
And Pena Jr. has never forgotten what his dad taught him. He is smiling every day, understanding that he is playing a game he loves, remembering his father's words: Have fun, and keep it simple. Play like you were a kid.
He always does. Just like his father.
Conor Nicholl is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.