PER Diem: April 16, 2009


Well, that was a nice how-do-you-do to start the playoffs.

We'd barely had an hour to sip our coffee and digest the matchups when news broke that Boston's Kevin Garnett was out indefinitely, and could miss the entire postseason.

This doesn't come as a huge shock to those who have been reading the tea leaves coming out of Beantown the past few weeks -- the nonspecific nature of the injury, the moving timelines, the fact he's been playing 40 minutes a game for the past 14 years -- all of which pointed to Garnett's being in some kind of compromised state for the playoffs.

But it's a bit jarring to hear he might not play at all. I had expected Garnett to gamely compete at 75 percent for about 20-25 minutes a night for the next few weeks, much as he tried to do two weeks ago when I saw him labor for 17 minutes in Orlando. I hadn't considered the possibility that the injury was so bad that he couldn't even fake his way through it.

Knowing that, the odds certainly shift on the chances of the Celtics' repeating as NBA champions. But how much? Can the Celtics still get past the Bulls? The Magic? And is it possible they could hold off Cleveland or L.A. even in their diminished state?

Let's dig into some numbers and take a look.

For starters, there are a couple of positives working in Boston's favor. First, while they don't have Garnett's actual presence on the court, they still have one of the by-products of his being around the team the past two seasons -- the Celtics' incredible defensive intensity and all-for-one chemistry. That's one reason Boston closed the regular season by winning 12 of 14 -- the only losses coming at Orlando and at Cleveland -- even without its star forward.

Additionally, there's another positive that's gone under the radar. While Garnett has missed the past month, so has his backup, Leon Powe. Powe returned to the lineup Wednesday night and had 18 points and 13 boards in a win over Washington, providing a good indication that he'll be ready to deliver in the playoffs.

In every respect but one, the difference between Powe and Garnett is less than you might think. Powe averages 17.5 points and 11.2 boards per 40 minutes, and shoots 52.4 percent; for Garnett those numbers are 20.3 and 10.9, and he shoots 53.1 percent. Additionally, Powe draws fouls by the bushel, while Garnett rarely gets to the stripe.

The major difference between the two is on defense. Garnett is among the best defenders in the league, of course, winning Defensive Player of the Year honors last season. Powe competes and takes lots of charges, but otherwise is average at best. Powe also averages a foul every 6.4 minutes, making it tough for him to get extended minutes.

Plus-minus numbers tell a similar story. On the season, Boston's adjusted plus-minus with Garnett was +5.87 points per 48 minutes; with Powe it was +2.79.

If you accept that there's about a 3-point difference between Garnett and Powe -- which both the plus-minus and per-minute scoring numbers seem to indicate -- then it's still a big deal for Boston. Three points per game is huge, and the real difference may be large: Powe's foul-proneness makes him unlikely to soak up 40 minutes a game in Garnett's absence, and the other subs aren't nearly as good.

For instance, if the distribution of Garnett's 40 minutes becomes more like 24 minutes of Powe and 16 minutes of Glen Davis (-6.40), then we're talking about nearly a seven-point difference between the Celtics with a healthy Garnett and the Celtics now.

To further validate that number, consider that Boston was 41-11 with a +9.5 average scoring margin when Garnett played 20 minutes or more, and 21-9 with a +4.0 average scoring margin when he didn't; allowing for home-court advantage (18 of those 30 games without Garnett were at home) turns it to +3.4 without Garnett and +9.8 with him, or a 6.4 point difference that's nearly identical to the seven-point estimate we produced above.

Here's the glass half full side of that story: Even at that latter level of production, the Celtics still are capable of having a decent playoff run. For instance, Boston's first-round opponent is Chicago, a team that gave up more points than it scored. So even with Powe replacing Garnett the Celtics have to be considered the favorite.

That said, you can see how losing Garnett could make for a much tougher series. Chicago had a home-court-adjusted scoring margin of +2.6 in the second half of the season after it acquired John Salmons and Brad Miller, putting it within a point of the Celtics' adjusted mark of +3.4. While a team with a superior scoring margin and home-court advantage usually wins, it's no longer beyond the realm of possibility for the Bulls to spring an upset, and at the very least the series could drag on a lot longer than it would otherwise.

In the second round, it's a similar story. Boston with Garnett and its +9.8 adjusted scoring margin would be a healthy favorite against Orlando (+6.7), especially with the Celtics' having home-court advantage. Plug in Boston as a +3.4 team, however, and it's less than 50-50 that the home-court advantage can save the Celtics.

It's certainly possible that they could reach the conference finals, in other words, because they have a relatively easy first-round opponent and home-court in both series. But it's no longer likely that they'll advance that far.

That's when we get to our second good-news, bad-news scenario. The good news: By the time the conference finals roll around a month will have passed, and if Boston can somehow survive that long it's possible that Garnett might be capable of playing (though we've been cautioned not to get our hopes up).

The bad news: Without Garnett, there's just no way the Celtics are beating L.A. or Cleveland. The Cavs had an average scoring margin of +8.9, while L.A.'s was +7.7 even with center Andrew Bynum missing a big chunk of time. The Lakers and Cavs each would have home-court advantage over Boston as well, so holding serve in TD Banknorth Garden would no longer be enough for the champs.

Thus, it seems likely that the Celtics' title defense is going to be far less impressive than we were thinking after they started the season 27-2. Garnett's spirit lives on to an extent in watching how the Celtics compete and defend, but there are few substitutes for a seven-foot perennial MVP candidate. Powe will do his best to make up the difference and it may help Boston survive a round, perhaps even two -- but it's a bummer to see that's the rosiest possible forecast for a team that looked so devastating half a season ago.

John Hollinger writes for ESPN Insider. To e-mail him, click here.