"That's their right, but it's frustrating from our end. But what can you do, right?" Nieuwendyk told ESPN.com of his discussion with veteran agent Pat Morris. "We'll just turn the page. But it's real disappointing."
Nieuwendyk had rolled the dice and decided not to trade Richards in March, who led the Stars with 77 points. The center now becomes an unrestricted free agent and could have as many as 10 teams interested.
The Stars likely will have to watch their star player walk away without receiving compensation.
Pierre LeBrun covers the NHL for ESPN.com.