So consistent is his excellence, it is easy to forget that Tim Duncan, at 31, has already won three titles and is chasing a fourth

	The Finals MVP in each of the Spurs' previous three title runs, Duncan has raised his averages in points, rebounds and blocks during the playoffs. Greg Nelson/SI

With heels splayed and toes pigeoned, Tim Duncan's anime-wide eyes are fixed on the floor 10 feet in front of him as he makes his telltale walk toward another NBA championship. It is the walk of someone with something on his mind that he doesn't wish to share. Is he confident ... or anxious? It's none of your business. Every night that Duncan steps onto the court from the San Antonio Spurs' bench, he carries himself like a baseball manager on his way to the mound: head down with his long arms seesawing to their own gangly rhythm, his face an inscrutable mask. The fans may be cheering or booing, but Duncan, bless his consistency, appears deaf to them.

There was a time five or six years ago, when he couldn't get his team past the Los Angeles Lakers, that Duncan's reticence was seen as a weakness. He was a team-first player then, too, yet he was criticized for lacking the fiery charisma, the bravado to inspire the Spurs. Those days are hard to recall now that Duncan's leadership and passion have set a standard beyond reach of his rivals. These playoffs should complete the makeover of Duncan from Shaquille O'Neal's victim to his heir: If he leads favored San Antonio past the Utah Jazz in the Western Conference finals (the Spurs led 3-1 after their 91-79 win on Monday night in Game 4) and then maximizes home court advantage in the Finals against the Detroit Pistons or Cleveland Cavaliers, his ring collection will match Shaq's -- and Duncan will have won his fourth at 31, three years younger than O'Neal was when the Miami Heat took the title last June.

The 6'11", 260-pound Duncan has emerged as the Jason Kidd of big men, a playmaker able to elevate his teammates from the low post. "In my 20 years in the NBA, Duncan is the best big to play the game," says former Houston Rockets coach Jeff Van Gundy. "O'Neal always had the benefit of a dominant perimeter player from [Penny] Hardaway to [Kobe] Bryant to [Dwyane] Wade. Duncan has had very good players -- [Manu] Ginóbili and [Tony] Parker are tremendous -- but he's never had that dominant player, so that's why I give him the edge."

If Duncan has avoided historical reckoning until now, it's because his versatility has made comparisons difficult. "The first decision that has to be made is, Are we going to talk about him as a post guy or as a forward? Because he's sort of both," says Gregg Popovich, Duncan's only NBA coach. "You think about guys like Kareem [Abdul-Jabbar] and Wilt [Chamberlain], and you don't think of Tim. Then you look at forwards like Elvin Hayes or Kevin McHale or Larry Bird, and you don't exactly think of Tim in the way that they played either. He's really an anomaly and has done both [roles].