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The New York Knicks may have reached an agreement to retain shooting guard J.R. Smith, but that doesn't mean the organization is finished adding pieces to its wing.

With Landry Fields agreeing to sign on with the Toronto Raptors, New York still has need for help, especially on the defensive end. New York could theoretically match the restricted free agent's offer sheet, but it would add three years and $20 million to an already bloated payroll.

Smith can spark the offense, but Fields was the glue-guy who did the little things.

Nevertheless, the Knicks may already have their eyes on someone else who can fill that role, according to Jared Zwerling of ESPNNewYork.com:

A source very close to Ronnie Brewer said the Knicks have expressed "some interest" in the six-year swingman. His team last season, the Bulls, didn't pick up his team option of $4.37 million, thereby making him an unrestricted free agent.

Brewer is a defensive specialist to the bone.

His jump shot shows neither the mechanics nor the results to make him much of a scoring threat. He made just under 43 percent of his field-goal attempts last season and remains most effective when slashing to the basket or taking advantage of the occasional offensive rebound.

Brewer was far more efficient when playing consistent minutes in three of his four seasons with the Utah Jazz. It probably didn't hurt that Deron Williams was making the most of the swingman's ability to cut to the basket off the ball and finish in the paint.

Furthermore, the athletic 6'7" guard isn't even close to being a factor from beyond the arc.

That being said, the Knicks' problem isn't offense.

They don't need Brewer to be a hero or even much of a complementary scorer. Head coach Mike Woodson would simply need him to reprise the role he played so effectively in Chicago.

If he can come off the bench and contribute some defensive energy to the second unit—and that's exactly where Brewer excels—he'll be plenty valuable.

He has long arms and quick hands, but he'll also stay in front of scorers and make guys on the perimeter actually work for their paychecks.

In other words, he's the perfect alternative to J.R. Smith, who never met a shot he didn't like. Though Smith can fill it up, he's a marginally competent defender who New York won't want to rely on in late-game situations against elite scorers.

Brewer would have to take a pay-cut to sign with the Knicks outright, so a sign-and-trade remains a possibility.

It wouldn't be the most earth-shattering move of the offseason, but it could be the kind of tinkering that keeps the club in contention. Whether defense still wins championships, it certainly doesn't hurt.