Dollars and cents: How the Thunder acquired Kendrick Perkins

Quality big men, especially those still in their mid-20s, rarely get traded. But the Thunder was able to capitalize when the suddenly cost-conscious Celtics realized they would have difficulty re-signing Perkins.

The Jeff Green/Nenad Krstic swap for Perkins/Nate Robinson then became a steal.

Boston is shelling out more than $80 million in player salaries this season. That's more than $20 million over the salary cap and more than $10 million above the luxury tax threshold.

The prospects of a lowered salary cap, and possibly a hard cap, in a renegotiated collective bargaining agreement quite likely would have prevented the Celtics from bringing back Perkins, an unrestricted free agent this summer. With a roster that includes a quartet of All-Stars in Rajon Rondo, Ray Allen, Paul Pierce and Kevin Garnett, Boston's payroll is already upward of $70 million for next season.

Boston's bind was evident in the four-year $22 million extension it recently offered Perkins, a deal Perkins turned down because it would have been far below his market value.

There are other reasons. The Celtics have a pair of O'Neal's, Shaquille and Jermaine, on the roster, so size isn't a problem. And Boston perhaps figured it would need more versatility for another postseason series against teams such as Miami, Chicago and San Antonio rather than a surplus of size for potential matchups with teams like Orlando and the Los Angeles Lakers.