The Miami Heat are not invincible.
We learned at least this much through one quarter of play this season.
They are especially vulnerable up front and they are getting less production from the point guard position than they have in years past.
Dwyane Wade, at times, has also appeared to be less than his usual superstar-self.
The Heat will be faced with these internal threats as they continue defense of their NBA championship. They will also be pushed by a collection of teams from the outside.
Fortunately, for Miami, most of those external threats to their throne reside in the Western Conference. In a potential NBA finals matchup, the Heat will need to beat one of those teams.
But that's assuming they move past the revitalized New York Knicks and out of the Eastern Conference, of course.
This list identifies the seven biggest threats to the Miami Heat's throne at the quarter-turn, assuming that they suffer no injuries moving forward. The statistics referenced are updated through Tuesday.
Miami Heat's LeBron James
The Miami Heat are not invincible.
Memphis Grizzlies Zach Randolph, Marc Gasol
The Memphis Grizzlies are constructed to capitalize on the Miami Heat's weakness at the center position.
Marc Gasol is scoring a career-high 15.7 points per game on over 50 percent shooting from the field.
He is combining with Zach Randolph to average over 30 points and 20 rebounds as a starting frontcourt tandem.
As a team, the Grizzlies are only allowing opponents to average 39.4 rebounds per game on the season.
Chris Bosh and company would have their hands full up front in a series with the Grizzlies.
For as good as Memphis has been through one quarter of the season, it's still hard to accept the idea that they can actually win the Western Conference.
They would obviously need to in order to threaten the Heat's title chances more seriously.
Miami Heat's Mario Chalmers
Mario Chalmers has started all 19 games for the Miami Heat through Tuesday.
In each of Miami's five losses, Chalmers is averaging four points on 27 percent shooting from the field.
For the season, he's averaging 6.3 points on 39.1 percent shooting.
The Heat's chances of defending their throne will continue to be threatened if they are not able to get more from their point guard position as the season continues.
While starting every game during the 11-12 campaign, Chalmers has averaged 9.8 points on 45 percent shooting from the floor. They need at least that much production from him again.
Similarly, backup Norris Cole is averaging only 5.1 points this season, as compared to 6.8 points a year ago.
Los Angeles Lakers Dwight Howard
Yes, the 9-13 Los Angeles Lakers are still a threat to dethrone the Miami Heat.
Eventually, the Lakers will correct some things in Los Angeles—we're assuming so at least.
Maybe that happens when Steve Nash returns to action, picking-and-rolling in coach Mike D'Antoni's offense like it was 2005 all over again.
Or maybe Pau Gasol helps turns things around when he returns.
On the strength of his superstar power alone, Los Angeles will remain a threat to the Heat for as long as Bryant is playing.
New York Knicks Carmelo Anthony
There is a chance that the Miami Heat will not even emerge from the Eastern Conference this season.
This type of threat did not really exist last year, if we're being honest with ourselves.
But this season it does, and it is the New York Knicks.
Carmelo Anthony is scoring 27.7 points per game, second only to Kobe Bryant in the NBA. More than that, though, Anthony is fitting into a team concept in New York for the first time since he's been there.
Jason Kidd has been an underrated acquisition for this team from a locker room and chemistry standpoint, and Tyson Chandler continues to anchor a defensive attack that allows only 95.3 points per game.
The Knicks have as good a chance as anybody to make things very interesting for the Heat this postseason.
Miami Heat's Dwyane Wade
Dwyane Wade has scored less than 16 points in five games this season.
In four of those five games, the Miami Heat lost.
For the year, he's averaging 20.2 points in 16 games. This is a much lower average than he has finished with in each of his two previous seasons alongside LeBron James in Miami.
That number is also Wade's lowest mark since 2004-2005. As a rookie, in 2003-2004, Wade averaged a career-low of 16.2 points per night.
If Wade's numbers dip closer to that career-low moving forward, the Heat's chances of repeating as NBA champions will decrease significantly.
San Antonio Spurs Tony Parker
I still wonder if the San Antonio Spurs could run with the Miami Heat in a seven-game finals matchup.
Maybe that's not fair of me.
At the same time, there is no way to discount the serious threat that the Spurs pose to the Heat's title chances this season.
San Antonio is clicking on all cylinders already, scoring 105.9 points per game as a team, and Tim Duncan is still amongst the games' most effective players this season, even at 36 years old.
Tony Parker is also putting up the same 18 points and seven assists that he did last season as an All-NBA Second Team selection.
In a tight game, it's always difficult to bet against a coach like Gregg Popovich, too.
Oklahoma City Thunder's Kevin Durant
Kevin Durant is playing like a man who will spontaneously combust into flames if he did not win the NBA championship this season.
He's shooting a career-best 50.6 percent from the floor while averaging 27 points per night.
He's also leading the Oklahoma City Thunder to an average of 106 points per game as a team through one quarter of play.
Where questions exist about San Antonio's ability to run with Miami, those same questions do not apply to the Thunder. The defending Western Conference champions are as athletic as Miami from top-to-bottom, if not more so.
Russell Westbrook is playing like one of the best facilitators in the NBA this season, averaging over eight assists per night. This is in addition to Westbrook already being one of the league's best athletes.
He's also a better No. 2 option to Durant right now through one quarter of the season than James has in Miami with either Bosh or Wade.