Injuries giveth, and injuries taketh away.

Less than a week after an injury to Miami’s Dwyane Wade provided new hope for the Knicks’ playoff chances, they received a crushing setback of their own yesterday. New York learned guard Jamal Crawford has a stress fracture in his right ankle and will likely require surgery that will knock him out for the regular season. (Although the always optimistic Knicks did note that Crawford could return for the playoffs. To do what? Watch the Nets?)

The news was a surprise, coming as it did after Crawford scored 20 points in the Knicks’ 99–93 victory over Miami on Monday. The win pulled New York within two games of the Heat and Orlando for the Eastern Conference’s final two playoff spots, and with Wade gone and the Magic floundering it seemed possible that the two local teams could seize the final two spots.

But now New York must try to make a playoff push without its second-leading scorer. Crawford’s 17.9 points per game aren’t always easy on the eyes — his shot selection remains among the worst in the game — but his absence leaves the Knicks shorthanded in many ways.

For starters, there’s the simple issue of bodies. Knicks coach Isiah Thomas has shortened the rotation considerably of late, and without Crawford there’s a major hole in the backcourt. My guess is that Quentin Richardson will slide back to shooting guard from his small forward slot and Jared Jeffries will return to the starting lineup. Given how disastrous Jeffries’s first campaign in New York has gone, this would be a major dropoff.

Crawford’s absence also means we’re likely to see more of Nate Robinson, which is both good and bad. On the one hand, Robinson replicates a lot of what Crawford does as a scorer, so the Knicks aren’t losing much in terms of point production when he’s on the floor. However, Robinson may have to play the point for long stretches — something Crawford normally did — and his tunnel vision tends to get him into trouble in that role.

That’s where another concern crops up, because Stephon Marbury isn’t 100% either. He’s been battling a sore knee and toe and was clearly hitting the wall before the All-Star break, when he had three straight single-digit efforts. It seemed the break did him some good — he’s got three straight 20-point games and five in a row in double figures. But with Crawford gone, Thomas will be tempted to run Marbury into the ground … especially once he sees Robinson run the offense for a trip or two.

On the “more bad news” front, losing Crawford also takes away the Knicks’ go-to guy in last-shot situations. Admittedly, the Knicks were getting way too predictable in this regard, so perhaps his absence will force some long overdue creativity from Thomas in late-game play calling. However, Crawford was the only Knick who could dribble the clock down to zero and get a decent shot off.

That is, unless Steve Francis comes back. And that brings us to the wild card in this whole proceeding. Because to assess the actual damage from the loss of Crawford, we need to know if Francis will return.

Francis is reportedly suffering knee tendinitis so severe that he might miss the rest of the season and could even be forced to retire. Of course, some have pointed out the coincidence that he played all five games prior to the trade deadline and none since, and wonder if there’s something more at work.

Nobody doubts there’s a problem with his knee; but neither Francis nor the Knicks have shown much interest in remaining tethered, and New York was working to unload him prior to the deadline.

In either case, Francis’s ability to return becomes paramount for the Knicks. Unlike Robinson, he can do a reasonable impersonation of an NBA point guard and so could help keep Marbury fresh. Additionally, his ability to create shots off the dribble could allow him to take over Crawford’s role as a lastsecond shot maker.

And for all the criticism he’s endured since that ill-conceived deal with Orlando a year ago, Francis has actually been pretty good this year when he’s played. He seems to accept that he’s not the alpha dog anymore, showing more concern for finding shots for teammates than in past seasons and forcing fewer jumpers off the dribble.

Unfortunately, he needs to be ambulatory for the next six weeks to be of use to the Knicks. If Francis can’t gimp out 10 to 15 minutes a night behind Marbury, then the two parties may look to part ways.

Francis still has two years and $33 million left on his contract after this season, but if his situation is deemed a “medical retirement,” insurance would cover most of it. That’s unlikely, though, as Francis is only 30 — we’re not talking about an Allan Houston situation.

A more probable alternative is a buyout agreement on the remaining dollars. That would save the Knicks a few ducats in foregone luxury tax payments — much as it did earlier this year with Jalen Rose and Maurice Taylor. The arrangement could happen as soon as this week or as late as this summer.

Presuming Francis can’t go, the Knicks will be scouring the market for healthy guards. If you’re not seeing any now, just wait a few days. Since the trade deadline has passed, several losing teams are likely to buy out veteran players that are heading into free agency — Memphis’s Chucky Atkins is one name that keeps coming up.

Whomever the Knicks add, however, is likely to deliver a poor imitation of what Crawford provided. It’s ironic that a Knicks roster most considered overloaded with backcourt players at the start of the year finds itself waylaid by an injury to a guard. But when you look at the horrifying combinations that result — Jeffries a starter? Ech!! Nate at the point? Agh! — and the missing scoring punch on a team that depends on its offense to win, it’s easy to see how Crawford’s injury could be the setback that puts the kibosh on the ‘Bockers’ playoff hopes.

Which is unfortunate, because just a night earlier the Garden was rocking, the Knicks were winning, and the playoffs seemed palpably close. A day later the backcourt is in shambles, and the postseason couldn’t be further away.

jhollinger@nysun.com