Jaylen Brown

Boston Celtics rookie Jaylen Brown

(AP Photo/Elise Amendola)

WALTHAM -- The day after the NBA Draft, Boston Celtics president of basketball operations Danny Ainge fielded a question about what separated Jaylen Brown from other candidates for the third overall pick. Looking around at the young players the Celtics had selected the previous night, Ainge pointed out the importance of entering the NBA with a strong physique.

"If you look down this row right here, (Brown) is playing in a man's league," Ainge said. "This guy is a man. Look at every one of these guys; (they) are grown men that can play physically in the NBA."

Brown has all the physical traits a team wants in a versatile wing: the wingspan of a big man, the mobility of a guard and enough strength to one day defend plenty of taller dudes. But with the 19-year-old just a rookie, the question bears asking: can Brown play the 4 spot in small lineups right away?

"Sure. Yeah," head coach Brad Stevens said Wednesday before Boston's second practice of the day. "I think so."

"Actually, I want him to get down the 3 first," Jae Crowder said with a smile. "Just get the technique of the 3 position before we start talking about him moving to another position. He's a rookie and a lot has been thrown at him in just a day so I don't want him to overthink anything. I know coach doesn't want him to overthink, just react as much as possible. As time comes, I think he will be able to be a guy like myself who can switch and guard multiple people."

On another team, Brown might be afforded the opportunity to make mistakes while trying to grow his game. He might get plenty of shots, all the minutes he could want, and the freedom of knowing it's OK to fail. But he happened to join the Celtics, who won 48 games last year and hope to improve on that record this season. They're focused on setting themselves up to win a playoff series, not catering things to their high lottery pick.

Brown's easiest path to the court might be at small forward, where Boston does not have much size behind Crowder. Gerald Green was signed for depth (and buckets) and Marcus Smart can guard bigger wings when he needs to, but there might be more opportunity on the wing than in the frontcourt. The Celtics options can throw Kelly Olynyk, Jonas Jerbeko or Amir Johnson at power forward, and Crowder will spend some time there too.

Boston is deep. That's obvious. Maybe Brown will still establish himself in the rotation immediately. Maybe he will stumble a bit as he adjusts to the NBA game. It's clear Stevens wants to simplify the transition to the extent he can.

"I think the biggest thing in playing the wing or playing the 4 is how much do you want to throw on him right now in the first day of training camp, right?" the coach said. "At some point, you've got an idea of everything that's going on around you but right now the biggest thing for all of our news guys -- Jaylen, Al (Horford), Gerald (Green) -- keep it as simple as possible so that you can be able to play basketball and do the things we need to do from a base standpoint. Then we'll move forward after that. Obviously, Al and Gerald are much more advanced just because of their age and experience. But Jaylen will catch up. He's really been enjoyable to be around. He really wants to be good. He's thoughtful. He wants to work at it, all that stuff."

Brown will have an athleticism advantage against a lot of small forwards, but his first step could become devastating if he learns how to slide up a position. At the other end of the court, the value of switching, interchangeable wings is clear. Brown and Crowder could emerge as a potent duo one day.

Until then, Brown has a great mentor. Crowder said "positioning and technique" were the most important lessons he learned while figuring out how to defend big men.

"It's much different than guarding a perimeter guy," Crowder said. "You just got to get comfortable with technique and knowing tendencies of players. Not just at the 3 position or at the guard position, you have to know the tendencies of the 4s and the stretch 4s in this league. I just try to bring all that together and I'm a student of the game, so I watch a lot of film. I watch how other guys guard at their positions like Draymond Green and how he can be the same size as me and be effective on the defensive end of the court. Just tendencies and being in position at that position is what I've had to learn at a high rate."