Just 13 months ago, Diamond Stone was a baby-faced 18-year-old walking across the stage as a newly minted graduate of Whitefish Bay Dominican High School.

Of course he was also a 6-foot-11 man-child and four-time state champion whose prodigious talent made him one of the best basketball players in the country and among the most highly recruited preps – along with Rice Lake and future Marquette star Henry Ellenson – ever to emerge from Wisconsin.

But a little more than a year ago, Stone was still only a kid, shy and reserved away from his family and friends, with a demure personality that belied his dominant play on the court.

Fast forward to Monday, when Stone worked out for the Bucks, one of nine training sessions he’s participated in for NBA teams in advance of Thursday’s NBA Draft in New York, where he very much hopes (and plans) to be a first-round pick.

Following the workout, Stone met with the media to discuss the professional preparation process he’s gone through since declaring for the draft after one season at Maryland and spoke – still in his soft voice – with the quiet confidence and self-assuredness of a player expecting to hear his name called early. Perhaps much earlier than anyone else is predicting.

"I know what I’m capable of doing; I know that I’m one of the best bigs in the draft," Stone said at the Cousins Center. "I personally know that and I’m pretty sure these coaches and GMs know that too. My job is to go out here and just compete and show them all my talent."

Considered a possible lottery pick before his freshman year and projected as a late first-rounder by the end of the season, Stone’s name has appeared in the second round in some recent mock drafts. 

He doesn't think he’ll fall that far.

"I hope not," Stone said laughing. "But I really don’t know. It’s too early to tell. I don’t really look at the mock drafts. The GMs don’t think that at all."

Stone said the feedback he’s gotten from pro evaluators is "pretty good." Bucks general manager John Hammond was in attendance Monday, as well as head coach Jason Kidd and several others. Milwaukee owns the ninth overall pick in the draft.

"All my workouts have been strong," Stone said "I’ve been going hard, competing at a high level, so I think that hopefully my chances of going lottery or first round are very high."

Thank You @Bucks For Having Me Today✅

— All Eyes On Me (@Diamond_Stone33) June 20, 2016

Considered one of the top first-year players in the nation when he enrolled at Maryland – following a high-profile recruitment that left many Wisconsin fans feeling angry and flinging hate about why the McDonald’s All-American had spurned the Badgers – Stone had an up and down year with the Terrapins.

Named to the All-Big Ten Third Team and the conference’s All-Freshman Team after averaging 12.5 points, 5.4 rebounds and 1.6 blocks per game in 2015-16, Stone exhibited both glimpses of greatness and omens of ordinariness.

On Dec. 30, in his first Big Ten game, he scored a Maryland freshman-record 39 points and grabbed a season-high 12 rebounds against Penn State. He had two other conference games with at least 20 points and finished the year with four double-doubles, displaying an advanced offensive game and immense potential.

But there were also games when he seemed to almost disappear, whether because of foul trouble, inactivity, frustration or lack of focus. During the NCAA Tournament, under the brightest lights, Stone shrank, averaging just 7.7 points, 3.7 rebounds, 4.0 fouls and 2.0 turnovers in three games. After Maryland lost to Kansas in the Sweet 16, Stone met with his parents and coaches and, unsurprising to most people, eventually made the decision to leave school.

"I just figured that it was time to take that next step, time to turn pro," Stone said.

He spent the next nearly two months at the IMG Sports Academy in Bradenton, Florida, where he trained four times a day, toning his musculature and improving his athleticism.

"I’ve been working hard," he said. "I feel like I’ve got my body in great shape. I need to get in better shape, but it’s in great shape, and I think that my shots are more consistent and my rebounding’s getting better. My explosiveness, just everything, off the charts."

Stone, who didn't attempt a three-pointer last season, certainly appeared to be more comfortable with his shooting. He was seen working with assistant coach Joe Prunty on Monday, sinking three-pointers with ease, and he told reporters he made 15 of 25 attempts from outside during his session.

"And that’s pretty good for me," Stone said with a laugh, adding that he’s been increasing his range and adapting to the further distance of the NBA three-point line. "Just knocking down open jump shots. I didn’t really get to show that at Maryland, but I realize in the NBA, if you’re open you have to shoot the ball. That’s my main focus is just knocking down open shots."

When asked what else he’s tried to improve and demonstrate to NBA evaluators during the workout circuit, Stone said, "Spreading my game, being more versatile; working on putting the ball on the floor and different moves."

One league executive, who agreed to discuss the pro prospects of Stone and Ellenson, said last month that his main concerns with the Maryland big man were intangible. He questioned Stone’s mental and emotional abilities more than his physical ones, saying, "He has to play with more consistent effort and energy" and also mature as a player.

That sentiment has been echoed a bit by others across the league. Gary Parrish, a CBSSports.com college basketball insider, said this is a mock draft write-up: "Stone has not helped himself in interviews, I'm told. And there are background issues that concern some franchises." Still, Stone’s size, talent and offensive skillset should be tremendously appealing to teams, especially those with picks later in the first round that could afford to let him develop more slowly.

But about those intangibles: Has the pre-draft process allowed him an opportunity to disprove the notions that he doesn’t have the work rate or blood-sweat-and-tears intense attitude desired by NBA teams?

"Yes, that’s one thing that I’ve been working on, too, is my stamina," Stone said. "You know, when people said I didn’t have a good motor, maybe that’s because I wasn’t really conditioned like that. So at IMG, I’ve been making huge strides getting my conditioning level high so that I can play a whole game or play hard the whole game. I think that my motor is getting better and better."

Stone also believes he’s made "huge strides defensively," another area scouts said was lacking. At 6-foot-11 and about 255 pounds, he’s got great size – as long as he’s still also got enough quickness to guard gifted opponents.

"That’s what I’ve been working on at IMG, my lateral movement," Stone said. "I realize that guys like Draymond Green, pushing the ball coast to coast, I have to be able to keep up with guys like that. I have to learn when to go for a block and when not to go for a block.

"So I think that if I stay the course and keep working on things like that, I could be an elite defender in the NBA."

Stone’s session included five other prospects – Michigan State forward Matt Costello, Oklahoma guard Isaiah Cousins, Notre Dame guard Demetrius Jackson, Oregon State guard Gary Payton II and Seton Hall guard Isaiah Whitehead – with varying projections similar to Stone, from the lottery to the second round.

"I love being around this environment," Stone said of the pre-draft experience. "I love competing with the best."

An admitted "bandwagon fan" who rooted for the Bucks and other teams while growing up in Milwaukee, Stone said it was "a real bonus" to be back in the city, especially getting to spend Father’s Day with his dad Robert.

"I was really looking forward to it," he said. "Come home and see my dad, spend some time with him, seeing my friends and family. It was a great weekend; great workout today."

Though he was happy to see the familiar faces, Stone noted that one of the off-court benefits of training at the IMG Academy, without loved ones around, was experiencing independence and approaching basketball as a job. 

"Just focusing on staying by yourself, because, you know, in the NBA your mom or dad’s not going to be there all the time," he said. "It was in Bradenton; it’s a small city ... so it kind of humbled me in that environment."

Stone hopes to be invited to the Draft at the Barclays Center in Brooklyn as one of the high-status "green room" prospects. He said he’ll be "very nervous" on Thursday, whether he’s in attendance at the event or watching with family and teammates on television.

"If I’m in the green room, it’s a dream come true, just seeing your name called and walk across the stage," he said. "Of course, I’d love to be in the green room. But if I’m not chosen, you just have to move on."

Stone’s no stranger to moving on.

Oftentimes over the past year, he was bludgeoned on social media and sports radio by Badgers fans deriding him for choosing Maryland. Many believed the decision was made because Stone didn’t academically qualify for Wisconsin, though Stone and others have dismissed that rumor. The vilification and insults increased after Stone earned a one-game suspension for an ugly flagrant foul against Badgers forward Vitto Brown in February.

On Monday, Stone alluded to the abuse he’s taken in responding to a question about what it would feel like to be a first-round pick.

"It would mean a lot," he said. "Just all the hard work, all the people that doubted me, especially when I was younger and I wasn’t very coordinated, all the people that were saying things like that, all the negativity with the recruitment, everything.

"I’m in the NBA, so it would mean a lot. But that’s just the first step. I’ll be a rookie again, like I was a freshman this year, so I have to start all over. And hopefully make a name in the NBA."

Just 13 months ago, he was walking across the stage as a high school graduate. On Thursday night, he plans to be walking across the stage as a first-round pick – "one of the best bigs in the draft" hoping to become one of the best players in the league.