At 28-0 and with many title belts piled up in his closet, Oakland’s Andre Ward looks to prove something to himself and start a new legacy Saturday night.

The former super middleweight champion is making his light-heavyweight debut against undefeated contender Sullivan Barrera at Oakland’s Oracle Arena.

“I want to be great, and these are things that great fighters do,” Ward said.

He’s out to conquer a weight class in short order, as a win Saturday on HBO probably would set up a megafight with WBO/IBF/WBA light-heavyweight champion Sergey Kovalev at the end of the year.

“Saturday is not a warm-up,” Ward said. “This is not a tuneup. This is a top contender, new weight class, serious fight.”

Ward hasn’t fought in nine months, and has fought only three times in the past four years because of injuries and a dispute with his promotional company. At 32, he knows it’s time to put the pedal to the metal.

“There was a list of three or four guys and Barrera was the toughest guy on the list,” Ward said. “This is the guy that’s going to let us know what this weight class is all about.”

Barrera (17-0, 12 knockouts) hasn’t fought anyone of Ward’s caliber, and Cuban boxing records are often more inflated than hospital costs. But Ward is not looking past Barrera.

“He’s technically sound, and has good power,” Ward said. “He is on the verge of breaking through, and I can’t let that happen. … If I lose this fight, there is no Kovalev. That humbles me and keeps me focused.”

Barrera did his part by calling out Ward on social media to get the fight.

“One of the main reasons that I targeted him was because he is considered one of the top three or four fighters in the world,” Barrera said. “I admire him a lot. … This opportunity is something that will prove to the world that I am at the top.”

Ward, meanwhile, said he is hungry, and also not as hungry as he used to be.

He explained:

“I relinquished my belt at 168 (pounds) so I am empty-handed. I’m hungry to get some more belts. … Everything I have done to this point, the book is closed.

“I feel like I did in ’09 when I was a young guy and I just signed on for the Super Six” tournament, said Ward, referring to a super-middleweight tournament that he eventually won. “It was sink-or-swim time, and I knew that if I lost, I was on the back of the bus.”

At the same time, Ward is smiling more than ever these days.

“That’s what everybody says and I tell them it’s because I can eat now,” Ward said.

He said that making the cut to 168 pounds wasn’t easy and it was “just a matter of when” he moved up a weight class.

“It’s dangerous up there at 175, but they have to deal with what I am bringing to the table, too,” said Ward, who has walked around at 180 pounds.

As a super middleweight, opponents underestimated Ward’s power. He has long been a gifted boxer on the inside who makes good adjustments. Ward said fans might see a “more economical fighter” at 32, but he will pounce on his chances to attack.

Those fans definitely push him, as this is his eighth fight in his hometown.

“Bay Area fans also come out strong, and it’s a good kind of pressure to put on a show,” Ward said.

It’s a bright time for Oakland sports, and Ward, a Raiders and Warriors fan, simply wants to add to the enthusiasm Saturday night.

“I’m excited for the city of Oakland,” Ward said. “Reggie McKenzie and Jack Del Rio are doing a tremendous job with the Raiders. And the Warriors … what can you say? I am just inspired.

“Steph (Curry) and I are friends, and he has perfected the game of basketball. He keeps going back to the lab, getting better and better. That encourages me to find reasons to come to the gym and get better. I want to make it look easy like Steph does.”

And that’s not easy.

Vic Tafur is a San Francisco Chronicle staff writer. Email: vtafur@sfchronicle.com Twitter: @VicTafur