HOUSTON - The Houston Rockets are going up for sale.

Rockets CEO Tad Brown made the announcement on Monday, hours after owner Leslie Alexander made the decision.

"It's been my great joy and honor to own the Houston Rockets for the past 24 years," Alexander said in a statement.

"I've had the incredible opportunity to witness true greatness through the players and coaches who have won championships for the city, been named to All-Star and All-NBA teams, enshrined in the Basketball Hall of Fame, and done so much for our franchise and our fans."

Alexander took over as owner in July 1993, and the Rockets went on to win back-to-back titles in 1994-95 behind the likes of Hakeem Olajuwon and Clyde Drexler.

In 24 seasons under Alexander, the Rockets have won 56.9 percent of their games, the fifth-highest in the league.

Brown said the 74-year-old Alexander had been approached over the years by potential buyers, but never considered it until very recently.

"I think it's been something he's been thinking about a little bit," Brown said.

"It can wear on you after so many decades, and he's tired. There are passions in his life now that are becoming more and more clear. His family, certainly, and his philanthropic efforts, what he'll be able to do with his additional time and his resources on a global scale is something that he's very much looking forward to."

Brown emphasized that Alexander is healthy and his health was not an issue in this decision.

NBA commissioner Adam Silver raved about Alexander.

"Leslie Alexander is a true competitor who always searched for the right move to make his teams better," Silver said. "Well respected around the league, he has been an active and influential owner whose vision helped to grow the game globally, especially in China."

Brown will be working with the league office while the Rockets look for a new owner.

There is no set timetable for the sale, but Brown said they want to find the right buyer and won't rush things.

"We're going to make sure that it is the right buyer," Brown said. "Leslie has the latitude of time based on our resources and his resources and everything associated with the team right now."

Brown would not say how much they expect to get in the sale.

Forbes named Houston the eighth-most valuable franchise, worth an estimated $1.65 billion, in its annual valuation of NBA teams last February.

Celtics sign Pierce for farewell

Paul Pierce is retiring as a Boston Celtic.

The Celtics announced on Monday they have signed Pierce to a contract so the 10-time All-Star, who spent the past two seasons with the Los Angeles Clippers, can retire with the team where he spent his first 15 seasons in the NBA.

Pierce helped bring Boston a title in 2008 as part the "Big Three," with Kevin Garnett and Ray Allen. He previously said that last season would be his final one in the NBA.

Drafted by Boston as the 10th overall pick in 1998, Pierce started a 15-season run that is behind only John Havlicek's 16 seasons for the most played in a Celtics uniform.

"It's an honor to have this opportunity to once again call myself a Boston Celtic," Pierce said. "The organization and city took me in and made me one of their own, and I couldn't imagine ending my career any other way. I'm a Celtic for life."