BOSTON -- While the Doc Rivers drama dragged out over nearly two weeks, the Boston Celtics didn't waste much time diving into Phase 2 of their rebuilding process.

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Kevin Garnett and Gerald Wallace will be switching jerseys this summer.Sources told ESPN on Thursday that Boston and the Brooklyn Nets have agreed in principle on a blockbuster trade that will send Kevin Garnett, Paul Pierce and Jason Terry across the Atlantic Division in exchange for a package headlined by three first-round picks (2014, '16, '18), Kris Humphries and Gerald Wallace. No trade between the teams can officially be consummated until July 10, when a league-wide moratorium on signings and trades is lifted after free agency begins July 1.

Where do we even begin? It's the end of an era in Boston. Not just these past six ultra-successful seasons since Garnett arrived, in which the Celtics ended a 22-year championship drought as the Big Three delivered Banner 17 in their first season together in 2008, but also Pierce's 15-year run with the team that drafted him.

But having watched their coach head westward, there was no room for sentimentality as the Celtics look to expedite the next rebuilding process. How serious is Celtics president of basketball operations Danny Ainge about speeding up this procedure? He is dealing Garnett and Pierce to an Atlantic Division rival, one he wouldn't even allow Rivers to interview with for Brooklyn's vacancy last month.