The Lakers have lost three straight games, most recently in Chicago to the Bulls, 95-83. Howard expressed dissatisfaction after taking just five shot attempts.
"When you lose games and you're going around after the game with a stat sheet in your hand and you're saying, 'Look at the stat sheet' to reporters and to your teammates -- you know what it is? It's passive-aggressive, immature stuff," said Van Gundy. "It's sad. This guy has so much to offer that is good for the game, to the game and to the Lakers. They're paying him huge money and they gave up a lot to get him."
Howard has already apologized for his comments, using the same keyword as Van Gundy, "That was immature."
Coach D'Antoni has struggled to blend the Lakers' roster together, especially defensively. The Lakers score 102.6 points a game. Howard has averaged 17.1 points on 58.2% shooting with 12.3 rebounds and 2.5 blocks.
He's also averaging 3.6 fouls a game along with 3.2 turnovers while shooting 50.4% from the free-throw line.
"Unfortunately right now his attitude towards the game is impacting his production on the court and the Lakers are not getting his very best," said Van Gundy. "At his very best he'd still be a dominant defender, rebounder and 18 point-per-game scorer. He doesn't like his role. You can see from his comments, from his play, he has very high role-frustration right now."
The Lakers have had a tumultuous season, starting 17-24 with multiple injuries and three different coaches (Mike Brown, Bernie Bickerstaff and D'Antoni).
"I think it's more dissatisfaction with his situation," said Van Gundy. "He wants to be the best player or No. 1 option offensively. I think it's impacted his entire game."
Van Gundy didn't hold back describing what he sees to be Howard's limitations.
"He has rudimentary offensive skills," said Van Gundy. "He's not a good ball handler. He doesn't have a really well-defensive low-post game - a poor free-throw shooter. But he can have a huge impact on the game defensively - rebounding, screening, rolling, the occasional post move because he's so athletic - but he doesn't want to do it that way."
While Howard, a free agent this summer, wouldn't talk about his long-term future with the team, he did say he believes the Lakers can turn their season around.
"I've just got to go out there and dominate defensively and make it tough for teams," said Howard. "I just have to get back to doing that and not worry about the offense."
The Lakers will try to break a six-game road losing streak on Wednesday night in Memphis against the Grizzlies.