Now, a year later, Rabb is older, wiser, more confident and less distracted.
"It's just another tournament now," said Rabb, Scout.com's No. 4 overall player in the class of 2015. "Being on the EYBL circuit, it's real big and a lot of fun. With all the best players, it makes it real competitive out there and guys give it their all."
A member of the Oakland Soldiers, Rabb has two legacies to live up to. He has to follow in the foosteps of the highly rated athletic forwards who previously ran with the Soldiers, players like: Aaron Gordon and Brandon Ashley. He's also been charged with helping the Soliders repeat as EYBL champions after winning the title this past July in Augusta.
Rabb said he's taking the pressure in stride.
"I don't even really think about all that," he said. "I know about it, but my teammates and I just want to come out and win games. Our only goal is to get back on track this year and win Peach Jam again."
On the court, Rabb's contributions come in nearly every facet of the game. He serves as the final line of defense before opponents arrive at the rim, is one of the team's primary rebounders and is its best post scorer. In a pinch, he's even stepped out and made shots from long distance.
"I think I'm a pretty versatile player," he said. "I get a lot of offensive and defensive rebounds, I'm good off pick and rolls, I finish around the paint and I'm a good communicator on defense. That helps me as a shot blocker too."
One frustration for many big men in an up-tempo setting, as many AAU tournaments are, is the inability of guards to precisely deliver the ball to the post. Rabb is no exception.
"Sometimes, because he's so dominant down low, it's hard for us to get him the ball," said Soldiers coach Jules Milstead. "Most kids get frustrated with that, but he keeps working. He's all in with what we're doing, has got his head on straight and is the real deal."
A standout at Oakland (Calif.) Bishop O'Dowd, Rabb claims offers from UCLA, UConn, Arizona, Kansas, Oregon, California, North Carolina State, Ohio State, UNLV, UNC and Arizona State.
The full extent of UNC's interest remains unclear, as the Tar Heels coaches have yet to watch him on this year's EYBL circuit and Rabb could not confirm a recent conversation with a Carolina coach. But, as Rabb disclosed last winter, he said Roy Williams called his mother in December and offered him a scholarship. While he has no immediate plans to visit UNC, he knows a lot about its program and its head coach.
"Roy Williams is a very good coach," the 6-foot-10, 207-pound Rabb said. "I watched them on TV a lot when I was younger and I still watch them now. They didn't have their greatest season this year, but they have a good staff and good players, so they're going to be good again soon."
At 6-10, Rabb doesn't want to become a wing player at the next level. He knows where he can do the most damage, and use his size to his advantage.
"(I model my game after) Kevin Garnett, Chris Bosh, Lamarcus Aldridge and Zach Randolph," he said. "I like playing inside. I like to bang even though I'm skinny. I know that when I'm older I'm going to fill out and can do more work playing inside."
The allure of being a traditional in-the-paint big man is one of the things Rabb likes about the Tar Heels.
"I love how they use their big men," he said. "I know this year they played four wings and one big because they had to. Even though there was only one big, they put him on the block and also brought him out some, they let him play, I like that."
Milstead didn't want to make a direct comparison to some of his former players at the same age, but said Rabb is on par with most of them.
"He's a pro, no question," he said. "You look at how young he is and he hasn't even matured yet. His potential is scary."