Tonight the son will be running up and down the parquet floor, the Red Auerbach court, trying to guard Paul Pierce and create some easy baskets for Kobe Bryant. The son will be trying to win a championship for the Los Angeles Lakers at the expense of the Boston Celtics. In the New Boston Garden.
The father will be 3,000 miles away, watching from his home in San Diego, feeling his heartstrings tugged in opposite directions.
Bill Walton the ESPN analyst has predicted the Celtics will win the NBA championship. It's his professional opinion, and a Celtics victory would celebrate everything he holds dear in his basketball life - Larry Bird, K.C. Jones, Paul Pierce - the Truth, justice, and the Auerbach Way.
But Bill Walton the dad is rooting for his son.
"There is nothing like the pride of a dad," Walton said yesterday from his home. "I'm a proud and lucky dad."
Luke Walton was a 7-year-old with a lion's head of hair when his dad wore No. 5 for the Celtics in the 1987 NBA Finals against the Lakers. Luke was the third of four Walton boys who regularly ran around the Celtics' locker room and practice site at Hellenic College.
"We used to terrorize the players," remembered Luke. "There were four of us and we got in a lot of trouble back then."
The Walton boys were all under the age of 10 when Bill bought the big house on Avon Hill Street near Porter Square in Cambridge in 1985.
"David Halberstam told me to buy the house in Cambridge," said Bill Walton, who's recovering from a pinched nerve in his back. "Best thing I ever did. I rode the T to the Garden for most games. Red Line to Green Line to North Station. With fans chanting, 'Here we go, Celtics, here we go!'
"It's impossible to overstate how better-than-perfect our life was in Boston. When you're on a special team, it changes your life forever. The Celtics, they didn't give me my career back, they gave me my life back.
"I just had no idea how special the life would be in Cambridge. I could ride my bike down to Harvard Square and play chess. The boys were on the swim team over at the Harvard pool, and we used the Radcliffe athletic facilities. It was just so perfect. I'm the luckiest guy in the world."
Visitors to Walton's big, drafty house came away dazzled by the chaos of a '60s-centric, Grateful Dead-lovin' California couple with four hell-raising boys. Opinions flew along with bats, balls, racquets, and Frisbees.
"I used to play pickup basketball on Sunday mornings at a court across the street from that house," recalled former Globie Jackie MacMullan. "There was always commotion. You'd see a ton of cars parked outside and hear loud music blaring.
"One morning, there was a lot of yelling and screaming and then I saw a pair of sneakers go flying out one of the windows. I asked, 'Who lives there?' and one of my friends said, 'Oh, that's Bill Walton's house.' "
Luke said there's no truth to the rumor the boys rode their bikes inside the Cambridge abode.
"Not in that house," insisted the 6-foot-8-inch forward. "That house was three stories, straight up. But we used to jump from the balcony down to the couch down below."
Luke Walton played in Waldon Park when he was a child in Cambridge. He went to Peabody School and Shady Hill School. A few years ago on a Lakers road trip to Boston, he went back to the old neighborhood with a cousin who was attending Harvard. Luke went up to the rambling old house and rang the bell but no one was home. He settled for a look at the playground where he'd sledded and skateboarded with Adam, Nate, and Chris.
"The hill wasn't as steep as I'd remembered," he said.
Luke and his brothers wore Celtics wristbands to school.
"Larry Bird was our idol. Even though my dad played on the team, we all had the Larry Bird shirts on and we'd go over to his house for dinner and play
Never allergic to hyperbole, Bill Walton summed it up like this:
"Luke got to see Larry play, and if you were ever in the Boston Garden, when Larry Bird was playing basketball, your life was never the same. The level of inspiration, dedication, and motivation - to go along with his remarkable talent - it was something that changed people forever and Luke saw that at the earliest of ages. His determination is a direct result of Larry Bird's brilliance."
Waxing poetic on the Celtics and the '80s puts Bill Walton on a roll. He can't stop. It's the verbal equivalent of hitting 21 of 22 floor shots in the 1973 NCAA Championship final against Memphis State.
"I've been hauling out some of the old pictures and looking at them. The thing about the Celtics is that they've always been about the family, the group, the team. And that's all that I ever wanted in my life was to be part of a special team. You couldn't wait to get to practice when you were on that team. There was that sense of community that you live for on a team and Boston-Cambridge had the same thing as a city. To have our children exposed to that at such an early age, it had a phenomenal impact and left an indelible impression on their souls.
"On some of the rare occasions that I would drive to the Garden, instead of take the T, Luke and his brothers would hide in the back of the car and I'd have no idea they were there. I'd have Jerry Garcia and Grateful Dead blaring and I'd pull into that back parking lot and as I was getting out, the boys - led by Luke - would jump out saying, 'We're here! We're going to the game! We don't care about going to school tomorrow!'
"Then there was the night of a big fund-raiser the Celtics were involved in. All the boys were dressed up in tuxedos with tennis shoes and they were about to go on stage and they started fighting. Adam reached over and punched Luke in the face, and bloodied his nose. Blood everywhere. The team doctor was there and wanted Luke to lie down and Luke said, 'No way! I am with the Celtics! I am going out on that stage.' With blood all over him, little Luke Walton went out there and basked in the glory of Larry Bird, Red Auerbach, K.C. Jones, and the legendary Boston Celtics."
The dad has been using his cellphone to motivate the son. Before each series, Bill called Luke and pretended to be a rival star, talking trash. Bill imitated Carmelo Anthony for LA-Denver and went with Carlos Boozer to get Luke ready for the Jazz. This week it was Bill Walton-as-Paul Pierce talking junk.
"Three minutes and 30 seconds of trash talking by Paul Pierce," said a smiling Luke. "It was pretty funny. At game time I have to listen to it again and pretend in my head that it really is Paul Pierce. Get the anger going."
"This goes way back," admitted the dad. "I verbally impersonate the antagonist in the drama. I have been leaving him voicemails, yes."
So, how to resolve this conflict of emotions?
"I think the Celtics will win," said Bill. "But I want Luke to win. I want what's best for Luke. There's nothing like winning the world championship. There's also nothing like losing the world championship. Both of those things stay with you forever.
"Those '87 Finals . . . we lost, and that was as low a point as I've ever had in my life. [That was the last time he ever played]. My lifelong dream was to play against Kareem in the Finals. I got there and I had a broken foot and I couldn't play and it's just devastating."
"I'm sure he's got to root for me," said the son. "He's got a lot of love for the city here and a lot of love for the Celtic organization. But you've got to go for blood first."
"There's nothing like the smile on the face of a young person," said the dad. "When that smile is on the face of your own child, it's just impossible to describe the feeling of happiness and satisfaction and pride. All the things that make the team, the city, the group so special - he's got a chance for that."
The series moves west Tuesday and Bill Walton hopes to make it to Staples Center for Games 3, 4, and 5. It's possible he could be on hand to see the series end a week from tonight . . .
. . . on Father's Day.
Dan Shaughnessy is a Globe columnist. He can be reached at email@example.com.