Howard's camp has informed the other four teams pursuing him that the free-agent center will not be signing with them, sources said Friday, leaving only the Rockets.
Howard has told the Los Angeles Lakers that he will not be re-signing in L.A., a league source told Broussard. A Lakers spokesman denied they have been told of Howard's intentions.
Dallas Mavericks owner Mark Cuban confirmed the Mavs are fully out of contention for Howard. The Golden State Warriors and Atlanta Hawks also have been told they are out of the running for Howard, a source told ESPNLosAngeles.com.
USA Today earlier reported Howard's final decision to join the Rockets.
Rockets general manager Daryl Morey wrote on Twitter that they have yet to be contacted by Howard, and that no deal is in place.
Not everyone on the Rockets will be happy with Howard's arrival. The addition of Howard would shift Rockets center Omer Asik to the bench.
Asik has no interest in being Howard's backup or playing next to him, a source close to the Rockets' center told ESPN.com. It is not yet clear if Asik will demand a trade.
A Lakers source who was in the team's pitch meeting last Tuesday, said they felt Howard had essentially "made up his mind" before even meeting with the Lakers and described him as "emotionless."
"He would barely look us in the eye," the source said.
Another Lakers source said "we felt like we were wasting our time" in the meeting.
Howard told an additional source that the main reason he's leaving the Lakers is because he wasn't comfortable playing for coach Mike D'Antoni, a source told ESPN.
Furthermore, Howard did not want to play 3-4 more years as a sidekick on Kobe Bryant's team, a source told Broussard, especially in a D'Antoni system that would rely heavily on 39-year-old point guard Steve Nash.
The Mavericks were the first team to confirm Howard had rejected its pitch.
"Got word we are out of the DH sweepstakes," Mavs owner Mark Cuban said in an email. "We gave it a shot and it didn't work out. It was truly an experience. At some point I will post our video and presentation we made."
Cuban said he had no knowledge of the free agent center's decision on a team.
"I have no idea what team he is going to," Cuban wrote. "They wouldn't tell me."
Also Friday, the Rockets agreed to trade Royce White, their 2012 first-round pick, to the Philadelphia 76ers for future draft considerations, according to Yahoo! Sports. The move gives the Rockets more flexibility to give Howard a maximum contract.
By going to Houston, Howard will leave $9.3 million on the table in net guaranteed dollars, because he could have received a five-year deal and more money from the Lakers, rather than the four-year maximum deal he will get by signing with another team. This assumes that Howard will be a resident of Texas instead of California, since Texas has no state income taxes, while California has the highest state income taxes in the country.
Comparing just the first four years of what the Lakers could pay Howard with what the Rockets likely will pay him, Howard will net $2.6 million more after taxes in Houston if he becomes a Texas resident.
ESPN The Magazine's Chris Broussard, ESPN's Marc Stein, J.A. Adande and Darren Rovell, ESPNLosAngeles.com's Ramona Shelburne and Dave McMenamin, and ESPNDallas.com's Tim MacMahon contributed to this report.