WALTHAM — Since the NBA stopped allowing prospects to enter the draft directly out of high school 10 years ago, the process lost some of its intrigue. Theoretically, that was good for NBA teams, which would like extra information before making multimillion-dollar decisions.

But for fans, there is also something tantalizing about mystery. And this year, there is Thon Maker, a 7-footer who will become the first player to go directly from high school to the NBA since 2005.

Maker, 19, was granted eligibility through a slight loophole. Players are required to be both 19 years old during the calendar year of the draft and also one year removed from graduating high school.

Maker spent this past school year at the Athlete Institute in Ontario, Canada, but his longtime guardian Ed Smith claimed that Maker actually graduated in June 2015 and stayed at the school for a fifth year, and the NBA accepted the petition.

Now, teams that have been watching Maker from afar as he played in high school tournaments and summer events are scrambling to gather more intelligence as the draft approaches. On Thursday, Maker completed a workout with the Celtics.

“I think with young players we’re looking at tools, right?’’ Celtics director of player personnel Austin Ainge said. “You hear it a lot in baseball, but in basketball, do they have height, length? What’s their skill level? What’s their competitiveness, their drive? We know that they’re not finished products. All young players, college freshmen, high school kids, European youngsters, we’re trying to look at the tools and try to imagine as best we can three or four years from now what they’re going to look like.’’

Maker was born in the Sudan and moved to Australia when he was 7. He came to North America during high school, bouncing from Louisiana to Virginia to Canada. As a sophomore, ESPN ranked him the No. 1 player in his sophomore class, and the expectations swelled.

Over time, though, some of the hype subsided, and Maker said he was just fine with that.

“I didn’t care too much about being ranked No. 1 or whatever,’’ he said. “I just cared about getting better at all times.’’

“There were times when I moved to Canada and nobody spoke about me, so that’s the same way I have to look at it. Nobody is speaking about you and you have to find a way to keep getting better. I did, and that’s how I got to this point.’’

Maker is now considered a potential late-first-round pick, although on Thursday he said he believes he could be selected in the lottery. He is a good shooter for his size and said he is capable of defending both small forwards and centers, but he is still quite thin and lacks explosive athleticism.

“I take pride in getting stops,’’ Maker said. “My offense, it’s catching up pretty fast, but that’s because I’m getting a lot of reps in. In these workouts, you’re getting a chance to show both, so by me having a chance to show offense at the same time, it’s helping me get better.’’

Shooting star

Former Kentucky guard Jamal Murray created a stir when he said he’d set the Celtics’ predraft record by making 79 of 100 3-point attempts during a drill in Wednesday’s workout. But it turned out Murray’s total was just the high for this offseason. Still, Ainge said, it was an impressive score. Ainge said that Celtics players sometimes have totals in the 80s, but added that it is not common.

“He’s a good kid,’’ Ainge said of Murray, “and he can really shoot.’’

The greater question surrounding Murray is whether he can play defense. Ainge said Celtics staff members Kenny Graves and Alex Barlow — former college guards — “got some good runs in [Wednesday] trying to attack him.’’

Big potential in town

Mamadou Ndiaye came to Boston for his first ever NBA game during the 2010-11 season mostly to see his favorite player, center Shaquille O’Neal.

Ndiaye is now one of the few people in the world who can actually look down on Shaq. The 7-6 center from California Irvine, took part in Thursday’s session. When he finished some brief media interviews, he wandered over to a display case that held O’Neal’s size-22 shoes.

“Wow,’’ said Ndiaye, who wears size-19 sneakers. “Unbelievable.’’

Ndiaye said he was “a little bit chubby’’ and was still shorter than O’Neal when he saw him play in Boston about six years ago. Now, he is 7-6 and chasing his own NBA dream.

This past season, Ndiaye averaged 12.1 points, 7.2 rebounds, and 2.4 blocks playing in the Big West Conference. He is not likely to be selected in the draft, but he should find his way onto a summer league roster. On Thursday, Ndiaye was asked if he was still growing.

“I don’t think so, but I hope so,’’ he said, smiling. “Maybe a couple more inches.’’

The Celtics on Thursday also worked out Alex Caruso (Texas A&M), Damian Jones (Vanderbilt), Georgios Papagiannis (Greece), Rasheed Sulaimon (Maryland), Robert Carter (Maryland), Stefan Jankovic (Hawaii), Shawn Long (Louisiana-Lafayette), Nik Slavica (Croatia), and Troy Williams (Indiana) . . . Celtics guard Terry Rozier on Thursday spoke to more than 1,000 students selected from 40 Boston-area middle schools to conclude the team’s Stay in School and Step Up Your Game programs for this year.