You can say this about Donnie Walsh: He’s patient.

While Isiah Thomas arrived in a blaze of glory, making a blockbuster trade for Stephon Marbury within days of taking over as team president, Walsh’s first few months in office have been much quieter. The only significant change has been the inevitable firing of Thomas and hiring of Mike D’Antoni as head coach, followed by two relatively low-wattage pickups in draft choice Danilo Gallinari and point guard Chris Duhon.

Meanwhile, the much-anticipated housecleaning of the Knicks’ overpaid malcontents hasn’t gained much steam, unless you think Renaldo Balkman was the quiet mastermind behind the whole underachieving operation.

Eddy Curry, Jamal Crawford, Quentin Richardson, Malik Rose, Jerome James, and Jared Jeffries are all still here, “earning” a combined $47 million this season between them. Even Marbury is still around, though rumors persist that he’ll be waived before he’s allowed to set foot in training camp.

But in particular, one move has been notable for its absence: Walsh hasn’t traded Zach Randolph yet.

This is important because if the Knicks are going to make their much-discussed free-agent splash in the summer of 2010 — the summer LeBron James, among others, becomes a free agent — they have to trade Randolph. There’s no way around this. His contract is so large that the math of getting far enough under the cap to sign James simply doesn’t work unless Randolph has been rerouted for a player or players whose contracts expire by 2010.

In other words: If they want LeBron, then Zach has to pack.

Walsh hasn’t lacked for opportunities. The Clippers had a big chunk of cap space after Elton Brand left, and they were prepared to take on Randloph’s behemoth contract to fill it, provided the Knicks threw in a couple other goodies as a sweetener. Walsh passed.

More recently, Memphis had a deal on the table that would have sent Randolph to the Grizzlies for Darko Milicic and Marko Jaric. Depending on whom you talk to, they might have asked the Knicks to throw in a draft pick and some cash, too.

The potential of this deal had Knicks fans in a lather for two reasons. First, Milicic is one of the league’s most notorious slackers and might be even more boo-able than Randolph, and second, Jaric is engaged to Victoria’s Secret supermodel Adriana Lima, who presumably would make a few cameos at MSG.

Alas, the Knicks passed on this one, too.

In each case, there may have been problems. For starters, including a draft choice in a trade is problematic for Walsh because of the blunders of Thomas, who threw a lottery-protected first-round pick into the Marbury trade that loses all protection in 2010. Since the league prohibits trading picks in consecutive years, this effectively means that the Knicks can’t deal a first-rounder until 2012, and nobody wants to wait four years for the payoff from a trade. Thus, New York would have to acquire a pick from a third team just to include it in a trade.

Additionally, the Memphis deal didn’t get New York all the way home on the LeBron James front. Jaric’s deal doesn’t expire until 2011, and while his fiancée may be easy on the eyes, his contract is not: roughly $7 million a year for a mediocre backup. (On second thought, he’s a bargain by the standards of the Isiah era. Sign him up.) Thus, the only way to reach the Knicks’ goal would be for Walsh to turn around and pay somebody to take Jaric off his hands, adding to the cost of the trade. Alternatively, he could go to the austerity model and lose David Lee to free agency next year, but this is even more unpalatable.

Plus, there’s the little matter of trading a high-scoring forward for a whole lot of nothing. I’m sure Walsh is hoping to get at least a little smidgen of quality in return for Randolph, given what a beast he is in the low post. And at the very least, I can’t imagine Walsh is very excited about throwing money into a trade after he just gave away Balkman to save a relative pittance (just more than $2 million).

So there are some good reasons why a Randolph deal hasn’t happened. But Walsh is also taking a risk by waiting, because it appears he’s going to enter the season with Randolph as a Knick and then try to move him later, probably at the February trade deadline.

This just might work. Once the games start, teams might notice Randolph’s boorish behavior less, and his huge frame, soft touch, and refined low-post game more. Remember, it would be hard for him to play worse than he did a year ago, and he might be able to play much better — especially if D’Antoni isn’t hell-bent on pairing him with Eddy Curry the way Isiah was.

Additionally, the waiting game buys Walsh one less year of onerous contract to trade. From another team’s perspective, acquiring Randolph in February, when he has 2 1/2 years left on his deal, or next summer, when he has only two, doesn’t seem nearly as big a risk as taking him on now.

On the other hand, it’s possible Randolph gets hurt and lowers his value even further. Or that he’s involved in another “incident” that further stains his reputation and limits his attractiveness on the trade market. Already several teams won’t take a second look at him because of his rap sheet, and that list will only get longer if he doesn’t mend his ways.

But for now, Walsh doesn’t have much choice but to wait. Sure, he’d like to press a magic button and be rid of Zach in two seconds, but that’s not how it works. The reason Walsh was so successful in Indiana was because he didn’t force things — if there wasn’t a good deal to be had, he waited. And given that he still has two years to pull the trigger on a trade, the proper course is to be patient. Besides, we’ve already seen the damage an impatient executive can do.

So as hard as the thought of more Randolph may be to stomach for Knicks fans, who want only to see every vestige of the Isiah era erased from MSG as quickly as possible, it’s the best way to ensure as rapid a recovery as possible. As a result, we could be seeing Z-Bo around these parts much longer than we initially expected.

jhollinger@nysun.com