The Mavericks likely envisioned Harrison Barnes becoming a go-to kind of offensive player in the future, but not even the team (or, maybe, even the player himself) could have seen the transition from role-player to leading scorer going so smoothly so early in the season.

Barnes scored 19 points and grabbed nine rebounds in last week’s season opener in Indianapolis, hitting a game-tying 3-pointer with two seconds left to cap off a late Mavs comeback and force overtime. Two nights later, he scored a career-high 31 points on 12-of-23 shooting against Houston, although the Mavs would fall, 106-98. After that performance, head coach Rick Carlisle showered his new forward with praise.

“I expected Barnes to play extremely well,” he said. “I think he has a chance to be a very special player. I’ve felt that all along.”

OK, but this soon? Through three games, Barnes is averaging 20.0 points and 6.3 rebounds per game for the Mavericks, shooting 50.0 percent from the field, 45.5 percent from deep, and a perfect 7 of 7 at the free throw line. All this coming, too, with Barnes mostly playing power forward, with Dirk Nowitzki sidelined for the last two games as he recovers from an illness.

The 24-year-old is receiving an unprecedented volume of work early on with the Mavericks. Through three games, he’s taken 48 field goal attempts, and until Friday’s 23-shot outing, he’d never attempted at least 14 shots in two consecutive games in his entire career, per Basketball-Reference. That level of involvement means he needs to play differently than he has in years past.

“There’s a balance that I’m still learning in terms of when to make a play for others, when to be aggressive and not settle for a pull-up – get to the rack, get to the free throw line,” he said. “There are still things I have to learn in terms of being that kind of scorer.”

Not only does that expanded role increase his physical and technical demands — he’s got to pace himself and dig deep if he’s going to receive all those extra possessions — but it also heightens the mental requirements. You’ve got to out-think your opponent for 48 minutes in order to get the better of him.

Beginning with the preseason, you’ve seen Barnes carefully calculating in some situations, occasionally even passing up what would have been an open shot because he wants to try to make a play for a teammate or for himself. During one possession early in the season opener, he traded an open 3-pointer for a dribble-drive against Monta Ellis, whom Barnes thought was going to buy the shot fake. But Ellis stayed grounded and stripped the Mavs’ forward, resulting in two points the other way. That’s a five-point swing the Mavericks can’t afford. Other times, he’s in his own words settled for fadeaways or turnarounds in the post against smaller players, or pulled up for a jump shot against a slower defender, when he could have gotten closer to the rim instead.

One reason why he’s having to think so much? This is still new to him. He’s very good at this sport, of course, otherwise he wouldn’t be in the NBA. But he’s never been a go-to scorer in this league. For example, he’s already used 12 isolation possessions this season — 4.0 per game — while last season he didn’t even average one per game. (He’s scored 18 points in those situations, or 1.5 points per possession, which as of Monday was the top mark in the NBA, per Synergy Sports.)