Soobum Im-USA TODAY Sports

When I say Chris Andersen fills in the gaps, I don't mean covering every last opening on his body with a tattoo.

Andersen, in many ways, gives the Miami Heat what they lack and is an underrated cog in the championship machine.

Of key rotation players, he is top on the team in offensive rebounds per possession and is by far the top overall rebounder on the team. He also ranks on top in blocks per possession and field-goal percentage while committing fewer turnovers than anyone other than Shane Battier.

He is an efficient player who plays within his abilities, but that's not how anyone who watches basketball would describe him.

"His energy," Erik Spoelstra told Ira Winderman of the South Florida Sun-Sentinel, "for some reason, is contagious, it's infectious. And everybody starts to feed off of his speed, his energy, extra plays. He generates momentum for your team and he's getting in much better condition."

That's more like it.

When he joined Miami last January, the Birdman became a Heat fan favorite and an important asset on both ends of the court. But his impact can be overlooked.

He's also the team's most intimidating interview, which has to count for something.

Other than often being the only Heat player going for a rebound on a given play, Andersen is also a solid defender and a key part to Miami's offense near the basket. Here's how:

Rebounding

Robert Mayer-USA TODAY Sports

Miami is a team very much averse to rebounding. The Heat are dead last in the league in rebounding per possession.

Some of it is by design. The Heat would rather play with more perimeter players and give up an offensive rebound, trading size for additional scoring talent (in theory). More importantly, crashing the boards means sacrificing transition defense.

In fact, many teams in the NBA have given up on offensive rebounding, including Gregg Popovich's San Antonio Spurs and Doc Rivers' Los Angeles Clippers, both of whom join Miami in the bottom tier of the league in regard to the statistic.

However, unlike the Heat, those teams perform well on the defensive boards. The Spurs rank top-five in the NBA, and the Clippers, hovering around the top 10, are as good on the defensive boards as a "big" team like the Memphis Grizzlies.

The Heat are only better than the Milwaukee Bucks (bleh) and the Philadelphia 76ers (BLEH).

That's where Andersen comes in. Skim through the roster and you will find two players who give a crap about rebounding—Birdman and Udonis Haslem (Maybe you can convince me that LeBron James cares. Maybe.). Haslem is hardly allowed to play anymore, leaving Andersen as the team's lone rebounder.

He may only be averaging a shade below five rebounds per game, but his percentage of contested rebounds recovered is comparable to that of Joakim Noah, according to SportsVU data.

Andersen is often all alone to compete for a rebound, so that's an important stat.

(NBA.com/YouTube)

You can see in this shot that Andersen is the only Heat player with his head up toward the backboard. Chris Bosh, the power forward, is back-peddling away from the basket. James and Ray Allen both are turning to get onto defense and Mario Chalmers, who put up the layup, is behind Andersen and running away from his shot.

Again, this isn't a bad thing. It's by design. The Heat would rather give up the rebound rather than points in transition. But Andersen was able to keep the ball alive with a solid tip-in attempt (that he missed).

He is the lone player allowed to stay and compete for offensive boards, rendering his relatively impressive contested rebound percentage that much more important.

Defense

Being able to fight through screens and aggressively defend the pick-and-roll is key to Miami's chaotic defense. Birdman is really good at it.

In the clip above, Andersen is able to fight above a screen set by Jimmy Butler and stay on the hip of a driving Carlos Boozer. James plays some good help defense and gets between Boozer and the basket, while Andersen gets the block from behind.

It is a great individual effort within the context of team defense.

Birdzilla is averaging the most blocks per possession on the Heat by far and is part of the only two heavily used lineups that are allowing fewer than 100 points per game.

When he enters the game with Bosh, that frontcourt allows the fewest points per possession on the team.

Aside from the numbers, you know what you are getting when the Birdman enters the game. Tough, physical defense. Someone who will give the effort and all the cliches. For a team that has had its effort questioned on many an occasion, I have yet to hear that complaint directed at Andersen. Filling in the gaps.

Offense

With James, Bosh and Wade, the Heat don't need anyone else looking to get their points. Andersen lets the offense come to him. He does not force jumpers unless the shot clock demands it, and he is extremely efficient within his game.

Check out his shot chart.

NBA.com/Stats

Eighty-five percent of his attempts come from near the basket, from where he is converting more than 71 percent of the time.

What's more is that he's only attempted three shots just outside of his sweet spot—meaning that if he doesn't get near the basket, he won't settle for shots almost near the basket.

However, many of his points come off simple pick-and-rolls or from taking advantage of the gravity provided by his teammates in the form of cleanup putbacks and mini-cuts in space (like this).

With energy guys like Andersen, coaches don't necessarily need to call plays for him. The Birdman will find a way to help his team, whether it be by scoring, rebounding or defending. That's what he does. He fills in the cracks, and sometimes, he just doesn't get enough credit.

All statistics courtesy of NBA.com unless otherwise noted and accurate as of March 12, 2014. You can follow Wes on Twitter @wcgoldberg.