Who's better: Kevin Garnett or Paul Pierce? (AP)

Every so often a question is posed regarding the Celtics’ four All-Stars. In short: Which one is the most valuable/best/indispensable? What makes this question so intriguing is that there is a legitimate case to be made for all four.

Without Ray Allen‘s shooting ability the Celtics’ vaunted floor spacing begins to shrink and coach Doc Rivers loves to make use of Allen’s ability to use screens in their halfcourt sets.

Rajon Rondo is the playmaker, the only reliable point guard on the roster the last four years, and one of the few Celtics who can change pace and tempo with the flick of a switch. When Rondo has been out of the lineup — or gone through a prolonged slump — the Celtics inevitably struggle to score points.

Kevin Garnett is the defensive anchor and that doesn’t begin to do him justice. Simply put, when Garnett plays at the level he played at last season the Celtics defense is ferocious.

Then there is Paul Pierce, who does just about everything well and is the one player the Celtics reliably use to create his own shot when everything else breaks down.

You can go round and round in circles on this question and never come to a definitive answer, which is a large reason why this foursome has been so successful. Ubuntu may have been a clever rallying cry, but its tenets hold true for this collection of players. “I am what I am because of who we all are.” Take any one of these parts away and the whole suffers for it.

That’s why I watched with great interest as Sports Illustrated’s Zach Lowe unveiled his top 100 players list. One way or another Lowe would have to parse this group and assign a ranking. Lowe had Allen ranked 48th and Rondo 27th, which left the top spot to be decided between Garnett and Pierce.

In his latest update, Lowe has Pierce ranked 15th, just ahead of Garnett as the 17th best player in the league. To be fair, Lowe added this qualifier: “The next six spots, Nos. 19-14, represent the toughest stretch of the entire top 100 for me. You could order them in any way, and I wouldn’t have much of an issue.”

But rankings are rankings and here’s part of Lowe’s summation of Pierce: “Through it all, it is Pierce who has sustained as Boston’s best two-way player.”

That’s hard to argue. In early March I made the case that Pierce had been the Celtics best player and while the team proceeded to go into a prolonged slump that affected everyone shortly after the piece was published, the argument holds. Owing in no small part to an amazingly healthy regular season, Pierce was the team’s MVP last season.

While rankings and lists are always sure to inspire debate, there are a few more interesting takeaways from Lowe’s thoughtful list.

1. There are four Celtics in the top 50. While Lowe hasn’t rolled out his top 10 yet, a bit of obvious detective work indicates that only two other teams — Chicago and the Lakers — will have that many.

Chicago

47. Luol Deng

45. Carlos Boozer

43. Joakim Noah

TBA: Derrick Rose

Lakers

38. Andrew Bynum

33. Lamar Odom

TBA: Kobe Bryant, Pau Gasol

What’s interesting here is the gap between the other three Bulls players and Rose, which goes to the heart of the argument that Chicago doesn’t have a legitimate second star next to the league’s MVP.

The Lakers offer a bit of a different picture with two bona-fide superstars in the mix in Bryant and Gasol, which helps explain their two championships and three finals appearances over the last four seasons.

2. There are no other Celtics on the list from 51-100.

This indicates several things about the top-heavy makeup of the Celtics roster, mainly: The reason the Celtics didn’t win the championship wasn’t because the Big Four failed. Rather, it was because they had to do too much.

Beyond possibly Jeff Green and Glen Davis, it’s hard to think of other Celtics who would have been in the top 150 last season. Closing that talent gap is Danny Ainge‘s biggest priority for next season.

By the same token, the Celtics sought to defy conventional — and tested — wisdom that you need a top five player to win the championship. In 2008, Garnett was both a first-team All-NBA player as well as the Defensive Player of the Year. While Garnett was once again a first-team All-Defensive team member, none of the Celtics landed on the three All-NBA teams for the second straight season. That feeds the rationale that the Big Four’s time is past.

Due in part to the realities of the salary cap, Ainge is betting that the group has at least one more season of contending for the championship. While their individual talents may begin to diminish, their collective ability — when healthy, as always — remains intact.

All of that brings us right back to the beginning. The reason the Celtics have been so successful the last four seasons is not just because of the top-tier talent assembled by Ainge, but also because they blend so seamlessly. Ultimately, trying to determine which player is more valuable or more important is unimportant because they work so well together.

Still, Lowe’s ranking is yet another indication of the growth Pierce has made during the course of his career. It has been said here before and it’s worth repeating: The Celtics never would have come together so quickly if Pierce hadn’t so quickly and thoroughly adapted to his new teammates. He’s the one who has made the biggest changes to his game — not just in terms of shots and points — but in style of play.

Pierce’s willingness to change has helped propel him into the discussion of all-time Celtics greats and for now a deserved place as the team’s best player.