Star guards James Harden and Russell Westbrook were among a small group of Houston Rockets players and staffers who did not travel on the team flight to Orlando, Florida, on Thursday, sources told ESPN.
Each member of the group is expected to join the team later at Walt Disney World after traveling on his own.
Coach Mike D'Antoni was on the team flight, although he has yet to receive official word from the NBA that he has been cleared to coach the remainder of the season, sources said. D'Antoni, 69, said earlier this week that his medical screenings did not reveal any issues that would be considered red flags.
The league office informed the National Basketball Coaches Association that nobody would be placed in the high-risk category -- meaning they wouldn't be allowed to coach in the bubble -- due to age alone.
The Rockets' hopes of making a deep playoff run rest largely on Harden and Westbrook, two recent MVPs.
Harden has averaged a league-leading 34.4 points, 6.4 assists and 7.4 rebounds per game this season. Westbrook has averaged 27.5 points, 6.3 rebounds and 8.0 assists.