Red Sox lose key lieutenant (and top candidate to be Craig Breslow’s GM) to Nationals

As the season comes to a close, the Red Sox are losing a key member of their braintrust.

The Nationals intend to hire one of Boston’s assistant general managers, Paul Toboni, as their new head of baseball operations, a source confirmed to MassLive. ESPN’s Jeff Passan first reported the news. Toboni was one of two top Sox executives to interview with the Nats in recent weeks along with longtime lieutenant Eddie Romero .

“Ultra-aggressive with his ideas,” manager Alex Cora recently said of Toboni. “He’s a soundboard to a lot of people in the front office.”

Toboni, 35, was a fast-riser through Boston’s front office who was elevated to a senior vice president/AGM role under chief baseball officer Craig Breslow last winter. Breslow intends to hire a general manager (as his No. 2 executiv