Auburn Hills — There was a time when Derrick Williams had all the promise and upside he needed. As the No. 2 overall pick behind Kyrie Irving in the 2011 NBA draft, Williams looked to have everything in front of him.

Then the questions started: Was he a small forward or power forward? Where did he fit best?

At 6-foot-8, Williams dazzled in his two years at Arizona and was poised to continue with the Minnesota Timberwolves. Then more questions came, along with a spat with then-coach Rick Adelman.

From there, Williams fell into NBA purgatory, playing for six teams over the next five years. After playing in China for part of last season, he got a 10-day contract with the Lakers.

On Wednesday, Williams found himself in the Pistons’ free-agent minicamp with some other prospects from the development league, looking to get an invite to training camp in the fall.

The road to the NBA isn’t always a straight line.

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“It’s just part of the process. I have never heard of some of these guys — and that’s nothing against them; they probably haven’t seen me before,” Williams said. “It’s good to be all in a bunch and really get back to the basics. That’s why I’m here.

“I don’t care who’s out there on the court. I’m not focused on them; I’m focused on me and what I have to do to prove that I can get back to where I want to be.”

Williams was one of the oldest of the 18 players who participated in the two-day mini-camp. He’s looking to show that he still belongs in the NBA, but doesn’t have to worry about answering many of the same questions as before.

The league has changed significantly from those years, when being a tweener — a in-between player who can play two positions and flash varied skill sets — had a negative connotation.

Now, it’s huge asset.

“The NBA is going more toward hybrid (forwards) with Golden State starting that trend,” he said. 

“You have a lot of small guys on the court most of the game and when I first got drafted, the biggest thing was that I was a tweener — and now, that’s exactly what they want in the NBA.

“Sometimes, you have to just keep playing and when that opportunity does come, you have to showcase yourself.”

Williams shot a career-best 40 percent from 3-point range in 25 games with the Cavaliers in 2016-17, aided obviously by playing with LeBron James, but that could be something that another team is looking for in a free agent who just needs the right system to fit into to accentuate his skills.

That could be the Pistons, who don’t have a first-round pick and are mostly locked into their roster of veteran players, with very little wiggle room in terms of salaries. 

Anthony Tolliver, who had a standout year off the bench, could be gone because of the salary crunch. That could open a spot for a player such as Williams to play both forward spots.

After seven years in the NBA, Williams has his preferred road back, which doesn’t include a trip to the summer league or to the development league. 

He’d rather make a roster through training camp, without the bouncing back and forth with the NBA team.

That cost him last season, when he waited for an opportunity and had to play in China, where the chance came, but the skill level isn’t quite the same.

“It was a great experience. It was my first time out of the States and away from my family. Basketball was the main focus and for a lot of guys, that’s the reason they go to China,” Williams said. 

“I was keeping my head up and making sure I knew where I belonged — in the NBA — and making sure I was doing the right things.”

The rules are a different in China, which can present some challenges and some opportunities. 

Players from the United States are staggered so that the games don’t get lopsided, which can make for some interesting configurations.

“A lot of people don’t know the Americans can’t play together in the first and fourth quarter — only the second and third. The rules are much different and you have to get adjusted,” he said. 

“There are a lot of zone defenses. 

“It was great to just be by myself and regroup and make basketball the main focus again.”

Williams said he has more workouts, with the Celtics and Timberwolves, but it’s still a long road back. 

Basketball again is the main focus for Williams, but a team will need to see his skill set clearly and take another chance on him.