The Thunder apparently won’t sign a free agent this off-season — rats; I was hoping for the Cavs’ Anderson Varejao — but the key to this franchise is developing and retaining its own players. Sign Kevin Durant and Jeff Green to long-term contracts next summer, and Russell Westbrook the summer after that. And that task appears to be getting easier. According to an NBA memo obtained by ESPN, the league’s salary cap and luxury-tax threshold are expected to drop for the 2010-11 season. The cap for 2009-10 has been set at $57.7 million, down $1 million from 2008-09, with a luxury-tax threshold at $69.9 million, meaning any team that spends over that level will have to pay a dollar-for-dollar tax. And the memo suggests further erosion of revenues for 2010-11, with the cap estimated between $50.4 million and $53.6 million, with a luxury-tax threshold of $61.2 million. What does all that mean? Less money to spend on free agents, and since franchises already have the advantage in signing their own free agents — with longer contracts — the news should play well into the Thunder’s plans. The Thunder would do everything in its power to keep Durant and Co., but the price might not be driven as high under the current economic conditions. Locking up Durant and Green, with the ability to do the same with Westbrook a year later, fortifies the Thunder’s future. No franchise can stand pat. Eventually, all teams, good or bad, must add players via free agency. But adding role players is much less expensive than adding prime parts. "We have needs and things we want to address,” general manager Sam Presti said earlier this summer. "We’re not going to address them in one draft or in one summer. We could try to do that, but if we did, we’d be sacrificing value.” The NBA’s revenue outlook makes it appear easier for the Thunder to keep its core together.