"Yeah, he's back. I think he's done a great job," Kupchak told The Times. "There's been no discussions otherwise.
"He's made adjustments. He's been flexible. He's evaluated how he coaches as the season's progressed. He's listened to the players. He's very easy to work with and we think in particular since the meeting the day of the Memphis game, yeah."
D'Antoni is 40-32 since taking over as the Lakers' coach, though the Lakers are 28-12 since the day after a team meeting called by D'Antoni in Memphis in January.
D'Antoni, 61, has two more guaranteed years for a total of $8 million. The Lakers also owe former coach Mike Brown about $6 million over the next two years. Brown was fired five games into this season.
The Lakers have remained patient with D'Antoni.
"Much has been made of the injuries, and the coaching change [in November] and no training camp, which is certainly a part of it," Kupchak said of their up-and-down season.
"It takes a while. You're in New York coaching and you see the Lakers once or twice a year, you don't know the personnel. And the injury situation when he got here, Steve Nash had the broken leg. There's just too much going on to really look at it any other way."
D'Antoni resigned from the New York Knicks toward the end of last season.
Gambling website Bovada doesn't think Kobe Bryant will return in time for the Lakers' season opener in the fall.
The site was offering 3-to-1 odds he would be back in time and 1-to-5 odds he would not return for the season opener, which usually occurs near Oct. 31.
Bryant is out at least six to nine months because of a torn left Achilles' tendon.
Bovada also established two interesting over-unders for Bryant next season — games played (54.5) and scoring average (22.5). He played 78 games this season and averaged 27.3 points.
Lakers playoff tickets go on sale Saturday at 10 a.m. at ticketmaster.com, Ticketmaster outlets and at (800) 745-3000. There's a limit of four tickets per person per game. Tickets will not be on sale at the Staples Center box office.