What does ‘Adjusts playbook with a pencil, not a sharpie’ mean?

I was puzzled to find the headline – ‘D’Antoni Adjusts Playbook with a Pencil, Not a Sharpie’ in the sport article in today’s New York Times (http://www.nytimes.com/2011/03/04/sport/basketball ).

Although I understand ‘a pencil, not sharpie’ is a figurative expression comparing metal cylinder sharpie to wood pencil, what does it exactly mean? Adjust his hard style to softer style? Is ‘Adjusts playbook with a pencil, not a sharpie’ a kind of cliché?

The headline is followed by the following sentence:

Mike D’Antoni is fighting against perceptions, resisting his impulses and wrestling with his playbook. For years, D’Antoni cultivated an image and an offense based on speed and small lineups, constant movement and contrarian thinking. In Phoenix, that offense produced 60-win seasons and deep playoff runs. In New York, it re-energized a moribund franchise. But circumstances have changed, drastically.

I believe the analogy being drawn is between writing with a pencil — light colored, erasable, fine/hard to see; and writing with a Sharpie marker — bold, dark, permanent; with the point being that D'Antoni is less effective, or at least less revolutionary, in his new job than he has been in others. Think of solving a crossword puzzle with a pen vs. a pencil.

I read it as an implicit comparison of the nature of the Sharpie (an unerasable marker, generally making a heavy line) to that of the pencil (a lighter writer which can easily be erased or modified); D'Antoni is approaching his new situation with an eye toward making smaller changes that can be easily undone or adjusted to match his players, as opposed to coming in with a bunch of big ideas about exactly how things are going to work and making his players adjust to them.

The chief comparison here is that pencil marks are erasable while "Sharpies" are also known as "permanent markers" (not erasable).

The basic idea is that the person in question, when they make a change, is prepared to change it again if need-be.

Note that the part of the article you quoted talks all about changes.

I'd also like to point out that in the USA we call it "sports", not "sport". I generally let that one slide, but you linked an article in a USA paper, so you ought to at least know.