Help wanted: An executive to run Amazon’s sprawling retail and operations organizations at a moment when sales growth has plummeted and the company has dramatically overspent on warehouses and hiring. Readiness to be grilled by regulators in Washington, D.C. is a plus.

Those are the types of skills Amazon is likely to seek as it hunts for a replacement for Dave Clark, the company’s consumer chief and architect of its sprawling fulfillment empire, who announced on Friday that he will leave Amazon on July 1 after 23 years at the e-commerce giant. It was an unexpected resignation, coming less than two years after Clark became CEO of Amazon’s worldwide consumer business. In a sign of the suddenness of the move, Amazon’s CEO Andy Jassy, in a message to employees, didn’t name a successor to Clark.

That replacement is very likely to be a current Amazon executive or someone who has worked there in the past, rather than a stranger to its culture and increasingly complex business, former Amazon employees told The Information. Those people believe Jassy will pick a leader from its retail organization, such as Doug Herrington or Russell Grandinetti, or its operations group, such as John Felton or Alicia Boler Davis. But Jassy—who has previously helped recruit Amazon alumni to come back to top roles—could also turn to another “boomerang” candidate, such as Diego Piacentini, a former top executive in its consumer business.