The Mavericks signed Harrison Barnes to a four-year, $94 million maximum contract this summer, hoping he could grow into a franchise cornerstone. The decision was questioned at the time because despite his championship pedigree, Barnes had failed to have a major effect at the individual level in his four-year career and was awful in last year’s finals.

If his preseason play is any indication, the transition from role player to star will be harder than even the skeptics had imagined.

In seven preseason games, Barnes averaged seven points and three rebounds in 20 minutes per game while shooting 27 percent from the floor. He's missed 18 of his 21 three-pointers and has as many assists as turnovers. The concerns about his ability to take on more responsibility on a new team have been validated, at least so far.

It's preseason, which barely qualifies as NBA basketball. Teams are giving tryouts to players who are hoping to make the team and the rotations are not set. Most projected starters get a pass, and Mavericks coach Rick Carlisle doesn’t seem too worried.

"Shooting percentages have never been an important thing to me," Carlisle said, via ESPN’s Tim MacMahon. "I look much more at the process, the force, and conviction with which guys are stepping into shots. He's ready to go. He'll be ready on Wednesday."

But everyone is watching Barnes after his maximum contract. Unfortunately for the Mavericks, he’s been incapable of creating for himself or others throughout his NBA career.

The Warriors tried to make Barnes the captain of their bench in the 2013-14 season, and it went poorly. The same problems he had then remain. His handle is not tight or varied enough to allow him to drive in traffic. He almost always goes to his right, and since he can't get to the rim, he settles for mid-range jumpers or launches little runners and floaters that he lacks the touch to convert.

When Golden State needed a bucket from Barnes, they fed him the ball in the mid-post. He usually had mismatches, as Stephen Curry and Klay Thompson typically occupied the opponent's best defenders. He could even overpower or shoot over some wings.

Now that he's a featured option, though, he needs to score in different ways. His face-up game is serviceable but he's not a knockdown mid-range shooter and he lacks the explosive first step to get past defenders.

There are no new tricks in his game.

Worst yet, his lack of court vision is also obvious in those plays. He gets his blinders on when he has the ball and the offense grinds to a halt. He's using more possessions than in the past, but he's averaging less than two assists per 36 minutes so far, a lower mark than the already poor one he posted in Golden State last season.

It's too early to panic about Barnes, to be sure. He's just 24 years old and being asked to consistently do things he hasn't done before. Some of the looks off drives and post-ups that are rimming out now will go in later. The same applies for some of the three-pointers he's missing. He's a 37-percent career outside shooter who has missed at a high rate in preseason.

He also contributes in other areas outside of offense. Barnes is a decent rebounder and defender. His length and athleticism allow him to move up a spot to play power forward and to handle smaller players in a pinch. That versatility helped the Warriors reach the finals twice in the past two seasons, and should give Carlisle a lot of lineup options.

But is that enough to warrant a max contract? Second-year wing Justin Anderson provides similar spot up shooting and work on the boards at a fraction of the price.

What Dallas needed was a rising star to pick up the mantle and let Dirk Nowitzki fade into a secondary role. Nothing Barnes did in Golden State suggested he was that player. His play in preseason certainly won’t change that perception.

With time, Barnes might develop into the featured offensive weapon the Mavericks thought he could be. But for now, it looks like they’ve added nothing more than an expensive role player.