James Harden and Russell Westbrook may want out of Houston, but the Rockets don't appear to be in any rush to move them. A Rockets source told ESPN's Tim MacMahon that Houston is "willing to get uncomfortable" with Harden and Westbrook. That means potentially keeping the two of them into training camp and the season if the right offer does not present itself.
The Rockets have justifiably set an enormous price for Harden: "a proven, young star as a centerpiece along with a massive picks package," according to MacMahon. They are more realistic about their prospects with Westbrook, whose onerous contract limits which teams could theoretically trade for him. They are not at this time willing to give Westbrook up without getting assets back, either in the form of young talent or draft picks.
Harden's preferred destination is Brooklyn, but the Rockets feel no great urgency to send him to the Nets if they can't offer the right package. Brooklyn's best asset is Caris LeVert, who does not qualify as a proven, young star. The Nets have all of their own draft picks to offer, but a team with Harden, Kevin Durant and Kyrie Irving probably wouldn't pick very highly in the near future (though down the line, when those players retire or age out of stardom, their picks might become more valuable). Spencer Dinwiddie and Jarrett Allen are also attractive assets in a vacuum, but likely not difference-makers for Houston.
The Rockets have already traded Robert Covington for Trevor Ariza and two first-round picks. They are also reportedly trying to buy a draft pick late in the first round or early in the second. What they plan to do with those picks remains to be seen, but for now, it looks like Houston is going to play hardball with its two stars.