As the San Antonio Spurs face the possible end of an era, they attempt to repeat as NBA champions after a turbulent off season topped by LeBron James returning to Cleveland. Racism issues forced two team ownership changes, injuries hit stars Kevin Durant and Paul George and the league signed a nine-year television deal worth US$24 billion that begins in 2016 in the four months since the Spurs won their fifth crown by beating Miami in the NBA Finals. I understand what it takes to win a championship. I understand winning a championship is the hardest thing you could ever do LeBron James For all the Spurs have done over the past 16 seasons under coach Gregg Popovich, defending a crown has not been achieved, San Antonio's championships coming in 1999, 2003, 2005, 2007 and 2014. Spurs star big man Tim Duncan, who played on all five title teams, is in the final year of his contract and will turn 39 during the next NBA playoffs. The three-time NBA Finals Most Valuable Player (MVP) and two-time NBA MVP could be in his final season, as might Argentine star guard Manu Ginobili, who missed this year's World Cup with a leg stress fracture. But the Spurs are largely unchanged from last year, with French star guard and scoring leader Tony Parker signing a contract extension in the off season, countryman Boris Diaw back in a set-up role and 2014 NBA Finals MVP Kawhi Leonard returning with higher expectations. Australian reserve playmaker Patty Mills has a shoulder injury, but also will return this season. The Spurs dethroned "King" James and the two-time reigning champion Miami Heat last June, only weeks before the four-time NBA MVP left Miami for the Cavaliers, the home-region team he had spurned in 2010 to join the Heat. James signed a two-year deal with the team where he began his NBA career - setting up greater riches when new television money kicks in - and vowed to bring Cleveland a championship team, something it has not had in any major sport in half a century. "I understand what it takes to win a championship. I understand winning a championship is the hardest thing you could ever do," James said. "My expectations are still high, but I'm more patient now than I was four years ago." The Cavaliers inked a long-term deal with young star guard Kyrie Irving to show James they were serious about surrounding him with top talent for a title run, then made a trade deal to bring Kevin Love from Minnesota. "We're still putting things together on the court. It's still a process," Love said. "We'll get better. We just have to have some continuity out there. It will take us a while to get on the same page." The Cavaliers also have a new coach in David Blatt who has never guided an NBA club, although he coached Tel Aviv to a 2014 Euroleague title and Russia to 2012 Olympic bronze. The NBA faced adversity as racist remarks forced ownership changes for the Los Angeles Clippers and Atlanta Hawks. The Clippers' sordid saga surrounding Donald Sterling's taped remarks about not wanting his would-be girlfriend to bring black people to Clippers games ended with him banned from the NBA for life and selling the club for a record US$2 billion to former Microsoft boss Steve Ballmer. The Clippers boast star point guard Chris Paul and playmaker Blake Griffin and a top coach in Doc Rivers. Not having the nightly soap opera of scandal surrounding a play-off run could make the team contenders. Hawks co-owner Bruce Levenson said last month he would sell his controlling interest in the Hawks after a 2012 email becoming public recently in which he said, among other things, that "the black crowd scared away the whites". Hawks general manager Danny Ferry is also on an indefinite leave of absence after making racist remarks about African-born British NBA star Luol Deng. Kobe Bryant will return to the Los Angeles Lakers, but with star big man Pau Gasol now with the Chicago Bulls, little is expected from the once-mighty Lakers. The Bulls figure to be a contender with Gasol joining Joakim Noah and the much-awaited return of Derrick Rose, trying to overcome injuries that have sidelined him for most of the past two seasons. Also with diminished expectations are the Indiana Pacers, who lost Lance Stephenson to free agency and George for the season to a broken leg in an inter-squad scrimmage for the US team who went on to win the World Cup. Oklahoma City has lost four-time NBA scoring champion and reigning MVP Durant to a broken foot that could sideline him for two months, but with Russell Westbrook sparking the Thunder they should be able to hold firm until his return.