For the second time in two years, President Barack Obama has offered Julián Castro a chance to serve in his Cabinet, and the mayor has signaled his willingness to begin a swift process of confirmation to the post, knowledgeable sources say.

The process includes a vetting of Castro by the FBI — which has begun — and a Senate confirmation hearing, expected to conclude within months.

Castro, whose mayoral tenure thrust him into the national spotlight, refused to comment Friday. It was unclear what post the president has offered the Democratic stalwart.