Being described as a "tweener" in the NBA used to be considered a dirty word, an adjective used for a player too big or small to fit a traditional position.

The league, however, has evolved.

Now teams seek out players that have a Swiss-Army skill set that can fit into a more free-flowing, positionless game. There's value in being able to segue into multiple roles.

"I don't have the five positions anymore," Celtics coach Brad Stevens said. "It may be as simple as three positions now, where you're either a ball-handler, a wing or a big.

"It's really important. We've become more versatile as the years have gone on."

It's something players in summer league looking to earn a roster spot need to heed.

The 2017 draft was further proof of the NBA's direction.

The 6-foot-4, 195 pound Markelle Fultz went No. 1 overall and is the definition of a combo guard. He has elite scoring ability, but also is a facilitator as a point guard. The 76ers plan to use him at both guard positions and he's likely to start opposite 2016 No. 1 pick point forward Ben Simmons — another positionless model of versatility.

"My mindset is a basketball player," Fultz said. "I don't think I have any position, really.

"If they need me off the ball, I'm a play off the ball. I can bring the ball up. ... When I'm in those positions, I'm just trying to make winning plays to do whatever I can to win."

Sixers assistant coach Kevin Young added, "From a coach's standpoint, it makes the game from a tactical standpoint fun, because you have a lot of guys that can do a lot of different things."

The Celtics selected 6-8, 208-pound Jayson Tatum with the No. 3 pick and there have been questions about where he fits best. The Duke product could be a slight power forward and Stevens said the Duke product will even play some guard.

Tatum had 21 points, seven rebounds, three assists and five steals in his Utah Jazz Sumer League debut Monday and hit a go-ahead jumper with 5.7 seconds left.

"Tatum will play wherever," Stevens said. "He can handle the ball. He can move it. ... He's at least a wing because he can really handle the ball, too. And he can shoot it and do all those things. He's a very versatile player."

Boston is loaded with young multi-faceted players — Jaylen Brown, rookie Semi Ojeleye — with the key being the ability to guard multiple positions. That specifically comes into play against the pick-and-roll, where defenders can switch and still be in good position as opposed to having to fight through screens.

When Miami had LeBron James, Dwyane Wade and Chris Bosh together for four seasons and four trips to the NBA Finals, Heat coach Erik Spoelstra almost completely abandoned the 1-2-3-4-5 concept of assigning players certain roles and went to a positionless approach.

Spoelstra said James was a "1 through 5," a nod to both his offensive versatility and more specifically how he could guard any position on the floor. He believes having Swiss Army knives — in his parlance, someone capable of many things — is critical in today's NBA and was part of the reason why Miami took Bam Adebayo with the No. 14 pick in this year's draft.

At 6-foot-10, about 250 pounds, Adebayo has the body of a power forward. In Miami, he could be that and a backup center. And the Heat think he can stretch the floor, after seeing he had a shooting touch from deep in workouts that might have caught some by surprise since the majority of his baskets in his one season at Kentucky were dunks.

"You know us," Spoelstra said. "We don't care about positions. We don't care about conventional boxes where players fit in. We may play, who knows, five guys over 6-foot-9 next year in certain segments of a game without a point guard and make teams adjust to us. You have to have guys that have ability, have skill sets and we're looking forward to learning more about Bam's game."

Adebayo got a crash course in what that means in his first few days with the Heat. He also said Kentucky coach John Calipari introduced him to the concept last season, part of prepping him for where the NBA is going now.

"Positionless basketball, I compete with anybody," Adebayo said. "I've been competing against the best of the best my whole year at Kentucky. Cal made me switch every day in practice and made me switch in games. Just having that coming into the league, it gives you good experience."