Celtic Nation stood in the midst of devastation yesterday.

Dust and smoke filtered up from the debris piles. For the first time in 15 years, Paul Pierce won’t be a Celtic.

For the first time in six years, Kevin Garnett won’t be walking through the ceremonial Rick Pitino doorway.

The drained face of Boston-bred ESPN commentator Bill Simmons, whose disbelief spoke for all fellow members of the Celtic Nation, begged a wailing question that hasn’t been heard since the summer before Garnett came aboard.

What has Danny done?

In the name of rebuilding around Rajon Rondo, Danny Ainge has agreed to trade Pierce, Garnett and Jason Terry to the Brooklyn Nets for the cap-matching contracts of Gerald Wallace (three years, $30 million), Kris Humphries (one year, $12 million), MarShon Brooks (three years, $7 million) plus Keith Bogans, Kris Joseph and Tornike Shengelia.

The saving grace in this deal, obviously, is the three first-round picks coming the Celtics’ way, including one in next June’s much-hyped NBA draft.

The Celtics can look forward to their first trip to the ping-pong war room since the spring of 2007, because their current roster will produce higher picks than any of the picks they recently acquired.
Indeed, with the fruits of 2014 looming, and a shot at a franchise-level rookie, Ainge had to avoid a nostalgia tour by bringing back Pierce and Garnett.

Consider Ainge’s take Thursday night on the 2014 draft.

“Next year’s draft we don’t see as loaded. We see it as top-heavy,” he said. “(But) there will be more impact players next year.”

In other words, Ainge believes they have to pick among the top 10 to make the trip worth their while. And they haven’t had a selection that high since the 10th pick of the 2001 draft — Joe Johnson. Pierce came to them on that same number in 1998.