Portrait of Oscar Robertson during the 2003 All-Star Weekend on February 9, 2003 in Atlanta, Georgia. The ‘Big O’ was elected to the Hall of Fame in 1979 and named to the NBA’s 50th Anniversary All-Time Team.

Henceforth and forever, the NBA should designate July 1 as Big O Day, in honor of Oscar Robertson, namesake of the rule that put NBA players on the road to free agency.

That road has been paved with gold ever since.

Robertson, 78, said he is open to the idea. “I like it,” he told me last week. “I don’t think a lot of players know anything about the Oscar Robertson Rule and what it really means.”

The rule has a number of ins and out, but what the players need to grasp is simple. “They should understand why they are making 15 and 20 million dollars a year playing basketball,” Robertson said.

Robertson v. National Basketball Association was a class-action lawsuit filed in 1970. Robertson at the time was president of the National Basketball Players Association. The NBA was represented by the firm Proskauer, Rose, Goetz & Mendelsohn, whose lead attorney was future NBA commissioner David Stern.

Robertson feels he has a good, not great, relationship with the NBA.

“I would have liked to have had a better relationship with the NBA,” Robertson said. “I really found out early that when I got involved with the Oscar Robertson case, along with other players as well, it sort of left a bad taste in the NBA’s mouth. They might tell you it’s not true, but I’ve heard it from other guys around the league I played with and some after that. I think they really resented that, to be honest.”

The intent of the suit was simple: Players wanted better playing conditions, and they wanted to make sure that when they no longer wanted to play for a team they were free to shop their services to the highest bidder.

The Robertson Rule sought to end the so-called “option clause,” under which a player was bound to a team for life — or until the team wanted to end the relationship.

In 1976, two seasons after Robertson’s retirement, the NBA settled. One of the most important provisions of the settlement was the Oscar Robertson Rule that effectively pit owners against owners in a bid to sign the best players.

When Robertson filed the suit, powerhouse teams were put together by owners on their own terms. Today’s star players can help put together powerhouse teams: LeBron James and Chris Bosh joined Dwyane Wade in Miami; Kevin Durant joined the Golden State Warriors.

“There’s going to be so many more things like that, it’s going to be unbelievable,” Robertson said. “We struggled and struggled. Now the pendulum is beginning to swing back our way. It’s not because of the rule itself but because owners want to win.’’

What Robertson and others set in motion represents a timeline that leads directly to free-agent-related movement that began to unfold just after midnight June 30, when free agency began.

On Friday, Golden State’s Stephen Curry became the NBA’s highest-paid player because the Warriors wanted to wrap Curry up before he hit free agency. Jrue Holiday agreed to a five-year, $126 million deal with the New Orleans Pelicans because New Orleans wanted to keep him from hitting free agency.

Robertson could never have predicted in 1970 where free agency would go, but it’s made the game better. Great players are coming to the NBA from all over the world. A league built on names and superteams has become star-studded.

“People want stars to play,” Robertson said. “They don’t want four or five guys on the team averaging 8 points a game. They want stars. They want people who can make the shots.”

In pushing hard for free agency, Robertson helped found the Church of What’s Happening Now. Old-school players have criticized the practice of playing with a stacked deck. Not Robertson.

“What’s wrong with a stacked deck?” he once told me. “I don’t think, in this day and age, one superstar is going to win.”

Robertson compared free agency to playing pickup ball on the playground, where you chose your team. “When you went down to the playground, if you got beat, you go home. So what do you do?” he said. “You look around and you get guys who can play basketball.”

I asked Robertson which team he would have chosen had free agency been available and which player he would have recruited to go with him.

“I probably would have gone with Wilt in Philadelphia,” he said, referring to Wilt Chamberlain, who played for the Philadelphia Warriors from 1959 to 1962 and again from 1965 to 1968. At the time, Chamberlain and Philadelphia couldn’t get past the Boston Celtics.

Just as the challenge today is beating Golden State, the challenge in Robertson’s era was knocking off the Celtics.

“I’m positive we could have enticed another player to come,” Robertson said. When I asked Robertson whom he would have recruited to go with him to Philadelphia, he laughed. “During that time? The player I’d take would be Elgin Baylor.” Baylor is the Hall of Fame forward who played 14 seasons in the Lakers organization, including his first two in Minneapolis.

There have been many important evolutions in basketball, from the jump shot to the emergence of Larry Bird and Magic Johnson. But there has been nothing as powerful as free agency.

Free agency has given players the right to earn substantial amounts of money and has also empowered players to speak their minds. “It made these guys instant movie stars,” Robertson said. “It gave them an opportunity to say things they would not normally be able to say and get away with it.”

Robertson feels — and I agree — that the players’ association’s next initiative is to get rid of the draft and let players negotiate with whomever they please.

The Cincinnati Royals selected Robertson with the first overall pick of the 1960 draft. Robertson did not win a title until 1971, after he was traded to the Milwaukee Bucks, which featured Kareem Abdul-Jabbar.

“For many years, I played here in Cincinnati, I was a victim of the draft,” he said. “The draft takes the best players and puts them on the worst team, and unless you have great management that can put other players together, you are not going to win anything.”

He pointed out how the current Philadelphia 76ers have stockpiled a menagerie of young players, so far with no success. “They get these players and they are going to struggle. They may win five or 10 more games, but they are going to struggle.”

Better to let the best young players negotiate with whomever they wish and allow the marketplace to take over. “But the NBA is such, all they’re looking for is cannon fodder for maybe three or four teams that can win the championship every year,” Robertson said.

The draft may or may not be here to stay. What’s certain is that, when the time is right, young players will benefit from the Oscar Robertson Rule.

“Big O day – sounds great,” said Michele Roberts, the executive director of the NBA Players Association. “Given the role the litigation played in establishing free agency, he symbolizes and represents the other named plaintiffs and entire membership that challenged the absence of free agency back in the day. For that, we are certainly all grateful.”

The best way for contemporary players to commemorate Big O Day in the NBA is to use free agency to its fullest. “Take advantage of it,” he advised. “You only come this way once. When it’s gone, its gone. You’re not going to be able to come back and play anymore.”

Oscar Robertson is one of the greatest players to ever play the game. He hears that all the time. Recognizing the first day of free agency as “Big O” Day is far more substantial.

The distinction memorializes a legend and gives deeper meaning to the life-changing freedom and independence that he helped usher in.