"Dwight is our future," Kupchak told "The Herd with Colin Cowherd" on ESPN Radio on Wednesday. "Kobe [Bryant] has one more year on his deal [this year, plus one]. That's all I can bank on or this organization can bank on. I have no idea if he wants to continue to play beyond next year. As of now, we're looking at a two-year window, [and that] plays to the urgency of the situation and how we build the team. ... This team's window to win is this year and next year."
When asked if he agreed with Kupchak and thought he was the future of the Lakers, Howard said at the team's shootaround Wednesday, "Yeah, I do. We talked about it plenty of times.
"Me and Mitch have talked about that all year," Howard added. "He just told me to trust him. So I'm going to trust him and go out there and play as hard as I can to try to get a title for the team this year."
However, when pressed over whether he will remain with the Lakers past this season, Howard stuck to his refrain of focusing on the present.
"The only thing that matters is right now," Howard said. "Nobody can control what happens in the offseason. Like I said to you guys before, there's no need to talk about it every day.
"There's no need for me to make a decision right now. My goal hasn't changed. I want to win a championship and I want to win one here. I'm here right now and this is our chance to get one this season. It's been tough, but we have an opportunity to change all that."
Kupchak reiterated his public stance that the 27-year-old Howard, who becomes an unrestricted free agent at season's end, is off the market with the NBA trade deadline looming Thursday at 3 p.m. ET.
"We've been very consistent," Kupchak said. "We're not trading Dwight Howard. ... He will not be traded, and there's nothing that anybody can do today to call me today and ask me, 'Would you do this?' and get a positive result."
Kupchak called Howard the best center in the league and expressed how difficult it is to acquire talent like him, especially with the restrictions in place since the league's new collective bargaining agreement was ratified.
"It's hard to get talent in this league, and to have a talent like Dwight Howard, we have no intention of trading Dwight Howard," Kupchak said. "He belongs to have his name on the wall [as a retired uniform] and a statue in front of Staples [Center] at some point in time."
The GM said he is not concerned with Howard's playful demeanor curtailing his effectiveness on the court and added that Howard will not be fully embraced until he earns a championship ring.
"Players in this league are not going to get their due until they win a championship, and until they do, they're under the microscope and they're going to be criticized for every single little thing," Kupchak said. "We've seen that with what's taken place in Miami in the last year or two. LeBron [James] is playing at a ridiculously high level right now, but for several years he was criticized for everything he did. When he won a championship, everything changed. That's just the way it's going to be. With Dwight, when he wins his first championship -- and he will -- people will look at him differently."
Howard's game has looked different this season as he's struggled to recover from back surgery and has been slowed by a torn labrum in his right shoulder. Howard's 16.3 points-per-game average is his lowest scoring output since his second season in the league, and his 11.8 rebounds per game are his lowest since his rookie season in 2004-05.
"Out of everything that's been going around, Mitch knows what we've been going through this year," Howard said following the Lakers' 113-99 win over the Celtics on Wednesday night. "He sees it, especially the stuff with my back. And he's fully supported me. He understands that I'm not where I need to be physically, but he continues to push me, to motivate me to get in better shape and play better.
"Mitch, he sees a lot of great things in me and he knows what I want to be at the end of my career," Howard continued. "He feels like this is the right place to do it. He's always telling me to do certain things, look outside my house, look at the city. Little things like that, just to motivate me."
Even with the drop-off in numbers, the Lakers are prepared to offer Howard a max five-year contract extension in the offseason and believe he will be able to return to the type of player who was the three-time defensive player of the year in Orlando.
"That type of [back] surgery takes at least a year to get back completely," Kupchak said of the procedure Howard underwent 10 months ago last April. "He's so young, he got back so quick, he's going to have a 100 percent recovery."
"I don't want anyone to feel sorry for me, but having back surgery is major," Howard added after the game. "It's not a bone, it's your back. It's not that easy to come back and play the way you want to play."
Kupchak acknowledged that Howard's relationship with Bryant is evolving, but said that was more of a product of them only playing half a season together than it was a personality conflict.
"I think it's a work in progress, probably the best way to say it," Kupchak said. "I would say the same thing about Kobe and Steve Nash and Steve Nash and Dwight Howard."
As for Pau Gasol, the other member of the Lakers' "big four," Kupchak said calls asking about the availability of the 12-year veteran have quieted since he suffered a torn plantar fascia in his right foot in early February.
"We're not going to trade Pau today or tomorrow, but his name has come up in the past, and it would be misleading to say it won't come up in the future," Kupchak said of Gasol, who will have a $19.3 million expiring contract next season.
Lakers coach Mike D'Antoni also isn't going anywhere anytime soon, according to Kupchak.
"Mike D'Antoni is going to be the coach here going forward," Kupchak said. "We're very happy with Mike D'Antoni. This is a very tough situation to walk into with no training camp, new players, a lot of injuries. There are no excuses there, whatsoever, because that's what all teams in this league deal with, especially the injury part, but he's brought energy, he understands the game, he's been great and we're very happy with him going forward."
While Kupchak is busy fielding phone calls leading up to the trade deadline, he is also processing the death of longtime Lakers owner Dr. Jerry Buss, who will be honored with a memorial service Thursday afternoon just hours after the deadline passes.
"The last two days have been very solemn around the office, and a lot of people [are] reflecting," Kupchak said. "We're going to miss him tremendously, but the franchise is in good hands. It really is. He made provisions to keep it in the family. My understanding is that's what's going to happen."
Information from ESPNLosAngeles.com's Arash Markazi and Ramona Shelburne was used in this report.