QueensCrap points us to a good interview with the Adrian Benepe, the City Parks commissioner. In it, he discussed the city's goal of putting a park within a 10 minute walk for every New Yorker:

That’s totally plausible. Already, three-quarters of New Yorkers live within a 10- minute walk of a park. We are continuing to build new parks.

The problem is what to do about those neighborhoods that are relatively park-less but also suffer from a lack of affordable housing. Adding more parks might make the housing shortage even worse. One solution, potentially unpopular and so far untested: using some of the park land for high-rise developments. Benepe also comments on this:

Well, I’m going to differ with your description a little bit here. Right along the edges of the land—which is not parkland—there will be two very small and discreet locations where there are some towers put up that will generate all the income needed to take care of the park.

Opponents say, “You’re building towers in the park.” It’s not quite a fabrication, but it’s an exaggeration. They are building some towers in a currently industrial area at the edge of what will become a fine park. The same way they built Riverside Park and Riverside Drive—a whole swath of real estate was developed along their edges.

For more info about the city's park plans, check out this informative PDF from NYC 2030 site.