OKLAHOMA CITY -- The Western Conference champion Oklahoma City Thunder are getting even younger.

With the core of the team built around 23-year-olds Kevin Durant and Russell Westbrook, the Thunder allowed three veterans who were over 30 to walk away in free agency this summer. That leaves forward Nick Collison as the team's only thirtysomething.

While Derek Fisher, Nazr Mohammed and Royal Ivey left, Oklahoma City added younger, unproven players to take their roster spots while saving room in their budget to sign NBA blocks leader Serge Ibaka to a contract extension and perhaps keep James Harden, too.

General manager Sam Presti says he's confident that Durant and Westbrook are ready to evolve into better leaders even if they aren't veterans yet.

Copyright 2012 by The Associated Press. All rights reserved. Material may not be redistributed.