By most tallies, the Knicks have two glaring problems in their backcourt. By mine, they have three.

As most basketball fans know, the Knicks have lost guard Jamal Crawford for the season (or the regular season, if you insist on being optimistic). The team also has to figure out what to do with Steve Francis, who has played a mere eight games since the first week in December. His knee problems are so dire that talk of retirement has surfaced from some corners of the Knicks world.

But there’s a third problem: what to do about the decline of Stephon Marbury. Marbury turned 30 last week, a number that is about as long in the tooth for point guards as it is for women tennis players. Stephon’s numbers took a nose dive last season, but much of that was attributed to Larry Brown’s inflexible coaching. Yet rather than rebound, his numbers have continued their downward slope. His points per game, assists per game, and shooting percentage are all down, and his minutes per game have remained fairly consistent.

This drop-off in production is particularly unfortunate because Marbury has played a savvy brand of ball this season. His turnovers are down, and he’s shown much more in the way of court leadership. Marbury has been instrumental in helping center Eddy Curry by getting him the ball in good position and, at times, directing the big man to the best spots to receive entry passes.

Still, it would be optimistic to expect Marbury’s decline to level off. Steve Nash and John Stockton are two of the only point guards who weren’t great rebounders (not Oscar Robertson, Gary Payton, or Jason Kidd) and didn’t decline precipitously after hitting the big “three-oh.” And that nasty moment when a decline turns into a free fall may happen sooner for Marbury since he entered the league so young. With last night’s game against the Boston Celtics, Marbury ran past the 30,000-minute mark for his career. That’s a lot of wear and tear on a body, even for an elite athlete like Marbury.

Although New York must first address the short-term problems, addressing the entire backcourt is crucial if the Knicks are to sustain the momentum they built this season. Unless Channing Frye takes the same big step forward that his friend David Lee took this season, next year will result in a leveling off, or even a fall-off, from this year because of the backcourt situation.

Obviously drafting Sergio Rodriguez, Jordan Farmar, Rajon Rondo, or Marcus Williams when the chance presented itself, and then taking forward Renaldo Balkman with their second, first-round pick last June would have been preferable, but no time machine exists (and if one did, can you imagine the volume of deeds that the Knicks brass might want to undo?). However, the draft is one place to begin addressing the longterm health of the backcourt. This summer, not picking a guard isn’t an option. And brace yourself for Isiah Thomas’s worst whims, but a backcourt player who can score and distribute is the first priority for the team’s midlevel exception. Just cross your fingers the need doesn’t result in the acquisition of a Marko Jaric.

The Knicks also need to track down a guard for now who might stick around for the long term, either via the waiver wire or from the Development League. The names of Development League options like former Knick Frank Williams, and former University of Portland standout Pooh Jeter are being bandied about in the blogosphere and may yield a better result than some bought out castoff looking for a winner. There’s no reason to repeat the fiasco that unfolded in Los Angeles when Doug Christie returned to action with the Clippers and then decided he lacked the motivation to play for a team that wasn’t in the title hunt.

For the time being the Knicks have to be smart about maximizing the value of their point guard. They need to limit his minutes particularly in back-to-back games, and, of course, they need to give rookie Mardy Collins a chance to run the point. Reserve guard Nate Robinson has demonstrated little ability to run the offense, but he will be a useful substitute for Crawford since both players take a lot of shots in spite of a relatively low percentage of success. It’s essential to look to replace Crawford’s scoring since his absence probably means more minutes for Balkman and swingman Jared Jeffries, neither of whom is a threat to score.

The Knicks have gotten themselves to an interesting position, right on the cusp of a playoff berth, something unimaginable during last season’s 23–59 debacle. How well they contend with the obvious backcourt problems will determine how long into spring their season lasts. How they deal with Marbury’s current and continuing decline will determine if they are able to sustain this improvement into next season and toward that day when cap flexibility returns.

mjohnson@nysun.com