According to Marc Stein of the New York Times, Harden instead attended a birthday party for rapper Lil Baby in Atlanta.
TMZ Sports reported Harden gifted Lil Baby a $200,000 Richard Mille watch and $100,000 in cash.
New Rockets head coach Stephen Silas said he expected Harden to be present for the team's first practice Sunday, per Stein.
ESPN's Adrian Wojnarowski reported last month that Harden is looking to be traded.
Specifically, Wojnarowski noted Harden rejected a contract extension offer from the Rockets that would have paid him $50 million per year and that he was determined to be traded to the Brooklyn Nets so he could join forces with Kevin Durant and Kyrie Irving.
In an apparent effort to appease Harden, the Rockets traded guard Russell Westbrook to the Washington Wizards this week for point guard John Wall and a lottery-protected 2023 first-round pick.
The trade came on the heels of reports that Harden and Westbrook no longer wanted to play together after just one season as a tandem. Following the deal, Wojnarowski reported it was Harden's preference to play alongside Wall rather than Westbrook:
While Wojnarowski also noted the Rockets are unsure if the acquisition of Wall will be enough to convince Harden to stay long-term, Houston doesn't need to make a decision about Harden any time soon.
He is under contract for at least two more seasons, so there is no reason to trade him unless the Rockets get an offer that is too good to refuse.
It is possible Harden could try to force the Rockets' hand by refusing to report to training camp, but he would give up a $41.3 million salary in 2020-21 if he decides not to play.
The 31-year-old Harden has been one of the NBA's best players since he was traded from the Oklahoma City Thunder to the Rockets in 2012 with eight straight All-Star nods, three consecutive scoring titles and one MVP Award.
Despite his offensive excellence, the Rockets have been unable to make it past the Western Conference Finals, including an exit in the second round of the playoffs in each of the last two seasons.
Perhaps Harden and Wall will be better suited for a deep playoff run than Harden and Westbrook were, but Houston needs Harden in camp before it can have any idea whether that is true.