In the NBA, stars play like stars, role players like role players. But on every team, there's at least one guy who's a major question mark. He could have a strong season and make a bad team respectable or a good team great. Or he could go down in flames and take his team with him. Who are these X-Factors for 2011-12? Take a look.

Smith is one of the most versatile players in the NBA, an explosive dunker, strong rebounder, adept passer and excellent defender. Yet he's never been an All-Star in seven NBA seasons, mainly due to inconsistency and a questionable attitude. At 26, there's still hope he will mature into the reliable star and team leader the Hawks need to compete with the top teams in the East.

O'Neal's first season in Boston was a bust. Plagued by injuries, he played in just 24 games, averaging 5.4 points and 3.7 rebounds. The Celtics need much more from their 33-year-old center now that the other O'Neal (Shaquille) has retired and Jeff Green will miss the season with a heart problem.

The Bobcats have some decent players. What they really need is a star. That's probably asking too much of Walker, the ninth pick of the draft after leading UConn to the national title. But Charlotte owner Michael Jordan says he sees some of himself in Walker, a 6-foot-1 point guard who is a natural scorer and leader. If that's even partly accurate, the Bobcats might not be all that bad.

The Bulls had the best record in the NBA last season but their lack of scoring punch was exposed in the playoffs by the Heat. Chicago replaced starting shooting guard Keith Bogans, who averaged 4.4 points last season, with Hamilton, a career 17.7 ppg scorer. At 33, Hamilton is a risk because his shooting percentage has plummeted the past two years, and he fell into coach John Kuester's doghouse in Detroit. But if he knocks down midrange jumpers and takes pressure off MVP Derrick Rose, the Bulls could be champs.

The rookie getting all the attention in Cleveland is point guard Kyrie Irving, the No. 1 overall pick who is expected to step in and become an immediate difference-maker. The Cavs' climb back to respectability will be much faster if Thompson, the No. 4 overall pick, is also ready to contribute. The 20-year-old power forward is more of a long-term project than the precocious Irving, 19, but he could help immediately as a rebounder and shot-blocker.

Odom was always the X-factor for the Lakers. On some nights he used his extraordinary all-around skills to make a major impact. On others he was a total nonfactor. It was frustrating at times but the overall result was positive: two titles with the Lakers and a Sixth Man of the Year award last season. Now, after a shocking trade to Dallas, the Mavs won't mind putting up with the same inconsistency if the power forward ultimately helps them defend their own title.

When the Pistons signed Gordon to a five-year, $58 million contract as a free agent in 2009, they thought they were getting an explosive scorer they could build around. Instead, he's averaged fewer than 13 points in two seasons in Detroit, seven fewer than his final season in Chicago, while seeing his field-goal percentage and minutes drop. Unless he earns his money, the Pistons' slide to irrelevancy is likely to continue.

The Nuggets got four players from the Knicks in the blockbuster trade for Carmelo Anthony. While none of them are stars, Denver is hopeful that Gallinari, 23, can develop into one. The 6-foot-10 forward is an outstanding shooter who plays with an edge. He helped the Nuggets go 18-7 down the stretch last season and will play a bigger role with Wilson Chandler and J.R. Smith stranded in China.

After striking out in their bids for free agents Tyson Chandler and DeAndre Jordan, the Warriors signed Brown to a one-year deal worth $7 million. Widely disparaged as one of the biggest draft busts of all time, the former No. 1 pick is still just 29 and coming off his best season with the Bobcats. If he can be a solid interior presence for the defensively challenged Warriors, he can take another step toward repairing his reputation.

The 7-foot-3 Thabeet was the No. 2 pick of the 2009 draft but has already been written off as a bust. Sent to the D-League and then shipped to the Rockets, Thabeet has no discernible offensive skills and is a foul machine on defense. But he's still 7-3. If he can block shots and protect the rim -- maybe a Dikembe Mutombo Light? -- Houston has the other parts necessary to be a playoff team.

As a rookie, George averaged 7.8 points and showed enough promise that the Pacers waved goodbye to Mike Dunleavy, Brandon Rush and James Posey. That frees more minutes for the 6-foot-8 swingman, who may be Indiana's most athletic and versatile player. With the addition of David West, Indiana could move into the East's upper echelon if George emerges as a threat on the wing to complement Danny Granger.

The additions of Chris Paul and Chauncey Billups should ensure a playoff spot for the Clippers. Whether they become a true title contender may depend on Jordan, 23, the league's most athletic center other than Dwight Howard. Though he averaged just 7.1 points and 7.2 rebounds, LA matched Golden State's $43 million offer sheet because of his potential as a dominant defender. With no other center on the roster, the Clippers need him to develop quickly.

He changed his name, danced with the stars and tried stand-up comedy. The question is whether the former Ron Artest played much basketball during the lockout. For the Lakers, there have been troubling signs that the mercurial small forward's lack of focus on hoops has resulted in a swift deterioration of his skills. If that continues, it'll be disastrous for a team that needs him to step into Lamar Odom's sixth-man role and take pressure off Kobe Bryant.

Gay is the Grizzlies' most athletic and highly paid player, so it raised eyebrows when Memphis thrived in his absence late last season. The franchise earned its first playoff series win without him, leading to questions about Gay's true value to the team. That's why it's up to the 25-year-old small forward to prove he can make Memphis even better, possibly by deferring to Zach Randolph as the team's go-to scorer.

Why weren't the Heat a dominant team last season, even with the Big Three? One reason is the absence of Haslem, who missed all but 13 regular-season games with a foot injury. Though he returned late in the playoffs, he wasn't himself, and Miami missed his toughness, rebounding, defense, midrange jumpers and leadership. If he brings all of those elements for a full season, no sure thing at the age of 31, the Heat may have everything they need to win a title.

Bogut broke his right hand and dislocated his right elbow in a horrible fall during a game two seasons ago. He played last season with limited use of his right arm and still averaged a double-double while leading the league in blocks. If he's close to full strength this season, he could easily be an elite center again and lead the Bucks to the playoffs.

Timberwolves fans have been eagerly awaiting Rubio's arrival since the team drafted him in 2009. After staying in Spain for two more years, he's finally here. But how good is he? His stats dropped last season with his club team and with the Spanish national team. His shot is suspect. But he's a precocious passer with the charisma of a star, if only he can play like one.

It's been a rough few months for Kris Humphries. His wife of 72 days, Kim Kardashian, filed for divorce. He was voted the NBA's most-disliked player. (Seriously?) And after hoping for a huge contract as a free agent, he returned to New Jersey on a one-year deal. Now the Nets, with center Brook Lopez sidelined by a broken foot, desperately need Humphries to set aside distractions and improve on last season's 10 points and 10.4 rebounds a game.

Most NBA fans didn't think much of Kaman's inclusion in the Chris Paul trade. (And judging by this picture, he wasn't thrilled about it, either.) But it was only two seasons ago that Kaman averaged 18.5 points and 9.3 rebounds and made the All-Star team. At 29, he could return to that form if he avoids the injuries that plagued him last season. Kaman and Emeka Okafor can give New Orleans a formidable frontcourt and a shot at the playoffs.

Davis may be the ultimate X-factor in that he'll miss at least the first month of the season with a back injury, then join a loaded Knicks team missing only a dynamic point guard to run Mike D'Antoni's offense. Davis has been dynamic in the past. He's also been erratic, oft-injured and unfocused. What will he be when he finally steps on the Madison Square Garden court? We'll have to wait and see.

When people talk about the young Thunder growing into a potential title team, they usually discuss Kevin Durant, Russell Westbrook and James Harden. But Ibaka, 22, is a key part of OKC's master plan. The 6-foot-9 power forward is still raw on offense, but he has a nice shooting touch (75% FT). Defensively, he's already a lethal shot-blocker but needs to improve his rebounding. If he matures quickly, the Thunder's future may be now.

Don't call him Big Baby anymore. Davis says he's all grown up and happy to be out of Kevin Garnett's shadow in Boston. He'll get a chance to play a bigger role for the Magic as Dwight Howard's buddy and frontcourt sidekick. If he can somehow make Orlando a contender, maybe he'll help convince Howard to stick around town a while longer.

The No. 2 pick of the 2010 draft struggled in his first NBA season, averaging just 7.2 points on 42.5 percent shooting. Turner, the national player of the year at Ohio State, is a jack of all trades but a master at none, so finding his niche was difficult. If he improves enough of his skills, particularly his shooting, the Sixers are hopeful he can blossom in his second season and help them at three positions: point guard, shooting guard and small forward.

The Polish Hammer was happy to escape from Dwight Howard's shadow in Orlando and take on a starting role in Phoenix, where he averaged 13 points and 9.4 rebounds following last season's trade. Now the Suns need him to take on a starring role for a team in decline. At 27, he could emerge as one of the league's better centers. He has the size and skills. Now he has the opportunity.

The Blazers had three young stars a few years ago. Now, because of injuries, one (Brandon Roy) has retired, one (Greg Oden) may miss another season and the third (LaMarcus Aldridge) recently underwent a heart procedure, though he's back on the court. That means Portland will have to rely on Crawford, its key free-agent acquisition, to shoot the Blazers into as many games as he shoots them out of. One thing's for sure: Crawford will keep shooting.

With the possible exception of Ricky Rubio, no NBA rookie will be scrutinized as closely as Fredette, who led the nation in scoring at BYU last season. Is he athletic enough to play point guard in the NBA? Will be be able to get off his shot? Can he guard anyone? The Jimmer looked good in two preseason games and may be the Tim Tebow of the NBA. If so, the Kings still might not make the playoffs, but they'll be fun to watch.

The Spurs are old. We know that. The question is whether they're done. That depends largely on the health of Tim Duncan, Manu Ginobili and Tony Parker. But an infusion of youth would also help in the person of Leonard, a 20-year-old small forward who was a voracious rebounder and defender at San Diego State. He needs to earn minutes from the disappointing Richard Jefferson and crash the boards to take pressure off Duncan.

The playoffs are a pipe dream this season. What the Raptors need is hope for the future. DeMar DeRozan established himself as a rising star last season. Now Toronto hopes Davis, also 22, will do the same. As a rookie, the 6-foot-10 power forward averaged 7.7 points and 7.1 rebounds, but he has the athletic ability to do much more.

The trade of Deron Williams left Utah devoid of star power in a league dominated by stars. In return, the Jazz got two first-round picks and a capable point guard in Devin Harris. But the key to the deal was Favors, the No. 3 pick of the 2010 draft. He was in over his head as a 19-year-old rookie. But the 6-foot-10 power forward could halt Utah's decline in a hurry if he becomes more of a force as a rebounder and defender. Stardom is the long-term hope.

The 7-foot McGee can run, jump, dunk, rebound and swat shots. What he didn't do last season was help Washington win many games. Like many of his Wizards teammates, the 23-year-old center just needs to grow up. The team-wise immaturity resulted in a pathetic 3-38 road record. With free agency looming next summer, McGee can make himself rich by showing more professionalism along with improved stats.