Garnett turned 33 in May. By all accounts, he takes terrific care of his body.

But he's also a guy who has always known just one speed. He plays hard all the time and it's bound to take a toll on his rail-thin body that just doesn't appear well-suited for NBA longevity.

Garnett and his surgically repaired knee will determine whether the Celtics' window to win another title is closed completely or whether the Big Three has an opportunity to finish their careers with multiple championships.

Garnett said he has been pain-free -- something that wasn't the case for much of last season.

"Better than anything, I'm playing without any pain," he said. "That's something I haven't had for some time now."

However, he also admitted that the knee is still sore at times.

Rivers maintains there are no restrictions with Garnett. Ainge said he expects K.G. to go through all the same drills as his teammates.

But no one truly knows for certain how he'll respond.

Not even Garnett.

In the spot next to the 2008 championship banner in the Celtics practice facility now hangs a blank banner.

"The players will know its meaning," Rivers said. "It's an obvious meaning."

But unless Garnett's knee truly gets back to 100 percent, it's meaningless.

Because it'll remain blank.