Out with the old and in with the old.

No sooner did one Hall of Fame coach step down, another walked back into the league with a new gig. Knicks fans will be familiar with both.

Monday’s first bit of news was that Pat Riley, who coached the Heat to a championship two years ago, decided to kick himself back upstairs in the wake of this season’s 15-67 disaster. Assistant Erik Spoelstra will take over.

Meanwhile yesterday, Larry Brown returned to the scene after a two-year absence, taking over as the new head coach of the Charlotte Bobcats.

Almost immediately, fans and the press began speculating on two thoughts — how long it would be before Riley intervened and made himself the coach again; and how long it would be before the infamously nomadic Brown clashed with management and started looking for his next job.

Let the power games begin.

We’ll start in Miami, where Riley oversaw an amazingly rapid decline of an aging Heat team that culminated in a train wreck of a 2007-08 season. He has always been regarded as a front-runner who walked away from jobs as soon as they got messy: In fact, he’s made this exact move before with the Heat.

Four years earlier, he stepped aside as the Heat’s coach in training camp and turned the reins over to Stan Van Gundy. After a year and a half, however, the Heat had drafted Dwyane Wade and traded for Shaquille O’Neal, and suddenly they were one of the league’s best teams.

Whoosh! In came Riley to take over Van Gundy, and it was he who was on the sidelines for the Heat’s title run in 2006. He deserves credit for squeezing a championship out of what was a fairly flawed Miami team that season, but his motives have been regarded with suspicion ever since. Last year, for instance, he took a leave of absence at midseason when Miami wasn’t playing well, only to return after assistant coach Ron Rothstein got the Heat back into the playoff picture.

So, one wonders how much rope new head coach Spoelstra will have. Spoelstra is a well-regarded Heat loyalist who worked his way up from being the team’s video coordinator. He’s a few weeks younger than the Nets’ Lawrence Frank, and thus wrested the title as the league’s youngest head coach away.

As long as the Heat are terrible, he’ll have nothing to worry about. But with Dwyane Wade, Shawn Marion, and a likely high first-round pick this year, the Heat may be back in contention soon.

If and when the Heat return to form, one wonders whether Riley can resist the siren’s call to swoop in and make another run at a ring, much as he did when he whacked Van Gundy.

Of course, his next coaching job may not necessarily be with the Heat. Riley has two years left on his deal with Miami owner Mickey Arison. After that, he’d be a free agent and would be free to pursue a job elsewhere. Given his track record, one presumes he’d have plenty of suitors.

In the meantime, he’ll focus on his team president role, a title he’s held throughout his Miami tenure. Riley’s history has been that he’s far more effective at this job when he isn’t coaching; that’s when he acquired Wade and O’Neal, for instance. With Miami in desperate need of a talent infusion, it’s hoped his renewed focus can speed up the process.

His competition in the Southeast Division will include another former Knicks coach, albeit one whose New York tenure was far less successful. Brown takes over for the deposed Sam Vincent, and will hope to guide the Bobcats to their first-ever playoff appearance.

Some of you might recall Brown’s last coaching gig: a disastrous 23-59 season with a Knicks squad that may have been the single most dysfunctional team in basketball history. Certainly many other teams did, which is why it’s taken Brown so long to find his league-record ninth team to coach — no other man has coached more than six.

Brown’s mistake was getting locked in a power game with the owner’s pet, then-team president Isiah Thomas. Hopefully he’s learned enough to avoid a similar situation with Charlotte team president Michael Jordan, who is as adored by Charlotte owner Bob Johnson as Thomas was by James Dolan — and might be about as bad at his job, too. Fortunately, the North Carolina connection the two share may be enough to reduce some friction, as the Tar Heels fraternity is a tight one.

Brown, though, is in a fantastic situation to rebuild his coaching reputation from the New York debacle. Charlotte is a bad team from whom little is expected, yet they have far more talent than many people realize.

Part of the problem this season was that Vincent did a dreadful job in his first and only season as the head coach. He left Nets castoff Jeff McInnis in the starting lineup for half the season for no apparent reason, struggled to find minutes for productive bench players such as Jared Dudley and Walter Herrmann, and baffled players with his rotations, strategies, and comments to the press. The concern when he was hired was how inexperienced he was, and it showed.

Obviously, Brown is experienced. He takes over a 32-win team that underachieved under Vincent, but he has plenty to work with. High-flying wings Gerald Wallace and Jason Richardson provide a solid nucleus, while big man Emeka Okafor could become an All-Defense player under his tutelage. The Bobcats also get back Sean May and Adam Morrison, both of whom missed last season after undergoing knee surgery.

It will be an interesting test of how strong the 67-year-old Brown’s faculties remain. The old Larry would have been a lock to whip these guys into shape at the defensive end and get them into the playoffs. But the Knicks’ train wreck makes some wonder if he’s become so manipulative that it’s impossible for him to keep the players’ trust.

For today, the news is that it’s one Hall of Fame coach in and another out. But everyone will be watching Riley and Brown closely to see what their next move is. Few people believe these are their last ones.

jhollinger@nysun.com