Jaylen Brown has been a man of multiple identities since being drafted third overall by the Celtics. The only way I can comprehend the rapid improvement is that summer league Jaylen, preseason Jaylen, and regular season Jaylen are not the same person. Maybe the University of California has a lab full of Jaylens that they release one at a time to push the limits of Jaylen technology. Maybe the first Jaylens were programmed in the 1980s, and that’s why he prefers the short shorts.

Summer Jaylen came in like a wrecking ball. Whenever the ball was in his hands, you knew he was going to streak to the basket, and you also knew the ball would probably not go in, but free throws would follow. Summer Jaylen is who we thought he would be after we did some homework after Draft Night ended. He’s a freak of nature athlete with a great game sense and a lot of room to go. The 16 points and six boards, and almost three steals per game were encouraging, as was the promised defensive instinct.

Preseason Jaylen shot 42 percent from the field but 27 percent from three. Brad Stevens gave him his deserved opportunities by playing him for the most minutes on average, and Brown converted that into 10.7 points per game—the third-highest on the team. The rebounds average was cut in half, and he only averaged one assist, but it wasn’t always an ordinary assist.

Preseason Jaylen continued to attack the rim with the same ferocity as Summer Jaylen but replaced some reckless dunk-on-your-face attempts with opportunistic wide open drives and even settled for some layups. He was ready for the regular season, but maybe not major minutes. The 23 he was allotted in the preseason seemed about right.

Fast forward to his fifth game as a pro, the second half of a back-to-back against Cleveland on the road. Jae Crowder, Al Horford, and Kelly Olynyk are all injured. Brown gets the nod to start in place of Crowder. LeBron James, winner of four MVPs and three championships took a fall away jumper in one-on-one cover against Brown about a minute into the game and missed. James’s next encounter with Brown came after he blew past Tyler Zeller, only to be disrupted from making a layup. Overall, James was two of six from the field when he was covered by Brown and 10 of 16 when covered by more Celtics—namely Marcus Smart and Jordan Mickey. Brown even got a piece of a floater LeBron tossed up on a drive, solidifying him as what could be one of the Celtics’ best options to guard James should they meet in the playoffs.

On the other end, Brown scored twice on James in three attempts, including a drive to the basket and an even stronger dunk.

Jaylen knocked down three of his six three-point attempts and shot eight of 16 overall in his first ever start against the top team in the conference. Even after shooting one of seven against Denver and zero for three from deep, Brown is still shooting 46 percent from the field 33 percent from long range, topping his preseason numbers.

Brown has now started two out of his six professional games, and players defended by him are scoring an average of .667 points per possession, putting Brown in the 89th percentile among all players. His 8.3 points per game his fourth among rookies, ahead of other touted prospects such as Brandon Ingram (6.6), Kris Dunn (6.4), Jamal Murray (3.3), and Dragan Bender (2.5). Keep in mind that the only rookie averaging more than 10 is Joel Embiid at 18.5. I won’t argue after six games that Brown will be better than those players in the long run, but I will say that he was at least the second most NBA-ready player in the 2016 draft class and that he’s one of the best decisions Danny Ainge has made in a long time.