He has been their rock, quite possibly the best individual defender in basketball, and without a doubt the best team defender in the game. He is their vocal leader and their last line of defense.
Defensively, he is their everything.
One of the most amazing aspects of Garnett's 2012-13 season is that while his offensive game has slipped slightly, his defensive numbers have actually gotten better.
According to Synergy Sports, KG is allowing just 0.75 PPP (points per possession) to the offensive player he is guarding this season, which the 31st-best number in basketball and among the best in the NBA for players who primarily play center.
Compare this to the 2009-10 season (the furthest Synergy goes back) when Garnett allowed 0.82 PPP, the 47th-best mark in basketball. KG has also improved his opponent shooting percentage—from 38.3 percent four years ago—down to 36.5 percent this season.
Despite the dip in his athletic ability, Garnett has become an even better defensive player this season, a testament to his greatness on that end.
But what about the rest of the Celtics' defensive abilities?
However, there is still plenty of defensive talent on the C's roster, and they'll certainly need that talent to shine in the postseason if they want any chance at all to make an extended run.
Let's take a look at the five Celtics that need to help Garnett on defense if the team is going to make any noise in the playoffs.
(Statistics courtesy of Synergy, Basketball-Reference.com and ESPN.com.)