The Rockets announced that rookie forward Royce White is not with the club in McAllen for training camp because of "personal matters."
White also did not attend the club's media day on Monday for the same reasons.
He told FOX 26 Sports the personal matters are related to the fact that he suffers from anxiety issues.
"We are trying to figure out a plan for me to be healthy and successful long-term," White said. "It's not really anything that's going on right now. It's more of trying to take a pro-active approach and trying to put together a solid plan.
"It is definitely linked with my anxiety sure, but it's not so much as far as my anxiety now. Basically what happened was my doctor, we discussed it, and it was decided the way the plan was now just wasn't logistically healthy.
"So what can we do strategically to try and improve the chances of everybody being successful in this situation, my success and the Rockets success? If I fail then that's not good for them either, because it's an investment."
White said he did not know how long it would take before he rejoined the team.
"We are committed to Royce's long term success and we will continue to support him now and going forward," said Daryl Morey, Rockets general manager, in a statement released by the team.
The Rockets drafted White out of Iowa State with the 16th pick in the first round of the 2012 NBA Draft.