Top stars on unfamiliar teams have revamped the set of contenders trying to dethrone the Los Angeles Lakers as National Basketball Association champions with the 2009-2010 season opening on Tuesday (Wednesday morning, Beijing time).

Massive center Shaquille O'Neal will join NBA Most Valuable Player LeBron James, who averaged 28.4 points and 7.6 rebounds a game last season, in trying to bring the Cleveland Cavaliers their first title.

"My mission is to win a ring for the 'King'," O'Neal said.

Veteran playmaker Vince Carter is among five new players who join Dwight Howard with the Orlando Magic as the reigning Eastern Conference champions cope with losing top talent, including Turkey's Hedo Turkoglu to Toronto.

"Vince gives us somebody who can create his own shots or create shots for somebody else," said Magic general manager Otis Smith.

Rasheed Wallace will join a healthy Kevin Garnett and Paul Pierce in powering the Boston Celtics while Richard Jefferson and Antonio McDyess join Tim Duncan, Tony Parker and a healthy Manu Ginobili with the San Antonio Spurs.

But the Lakers have made some changes of their own in a bid to repeat as NBA champions, swinging a deal with the Houston Rockets to bring in forward Ron Artest, a talented but often controversial figure.

"I'm coming to a team that already has a great nucleus of guys," Artest said. "I want to be a part of the team."

Kobe Bryant, who averaged 28.6 points a game last season, and Spanish big man Pau Gasol, who pulled down 9.6 rebounds a game, led the Lakers run to a 65-17 season and a playoff crown last season.

Now that they have won a title, the challenge will be for the Lakers to play as well in a repeat bid. Artest will provide the hunger as he tries to win his first NBA title and should work well in the Lakers' triangle attack.

Keeping Artest from becoming trouble or a distraction will fall to Bryant and Lakers coach Phil Jackson, who helped manage the eccentric Dennis Rodman during the championship heyday of Michael Jordan with the Chicago Bulls.

Lamar Odom and Andrew Bynum will play critical roles for the team as well, with Jackson wanting to stress defensive work this season, especially from Bynum.

"Offensively, he's doing great, but those defensive things have got to change," Jackson said. "That's where we want to make our statement as a team, defensively."

Much is expected from the Cavaliers after their 66-16 season ended with an Eastern Conference playoff upset.

"I wouldn't call it pressure but teams will be coming for us," O'Neal said.

A backdrop to Cleveland's season will be the free agency status of James after the end of the campaign, which figures to set off a bidding war for his services that a first-ever NBA crown would only turn into a King's Ransom.

The Celtics and Magic figure to be the East's other top title threats as they were a year ago but several other clubs will try and rise to that level, notably Toronto with Chris Bosh, Italy's Andrea Bargnani and Turkoglu.

Improvements from Luol Deng and Joakim Noah could lift Chicago while Atlanta made a move last year and Miami's supporting cast around star guard Dwyane Wade could revive the Heat.

Testing the Lakers in the Western Conference will be the Spurs, trying to return as a title threat with Ginobili recovering from an ankle injury to help Parker in the backcourt and Duncan aided by McDyess and Jefferson.

Dirk Nowitzki, the German star who scored 25.9 points and grabbed 8.4 rebounds a game last season, powers the Dallas Mavericks while Phoenix, led by Amare Stoudamire, will try to return to the playoffs with a quicker tempo.

Chinese star center Yao Ming could miss the entire season for Houston after foot surgery and with guard Tracy McGrady injured as well it figures to be a difficult season for the Rockets.