Jeff Wilke, a 21-year Amazon veteran who led its consumer business and was long thought to be a successor to chief executive Jeff Bezos, is retiring in early 2021, the company announced Friday.

As chief executive of Amazon’s Worldwide Consumer business, Wilke oversees its massive online marketplace, the entry point to the company for most consumers. Running that giant business, which accounted for the lion’s share of Amazon’s $88.9 billion in sales last quarter and its 876,800 employees, made Wilke the de facto No. 2 executive at the retail giant.

In a memo to employees, Wilke said he was not leaving for another a job and that he would retire in the first quarter of 2021.

“I don’t have a new job, and am as happy with and proud of Amazon as ever,” Wilke, 53, wrote.

He will be succeeded by Dave Clark, who currently serves as senior vice president of the company’s worldwide operations, Wilke wrote. (Bezos owns The Washington Post.)

In his own memo to staff, Bezos described Wilke as his “tutor” and touted the executive’s contributions to Amazon.

“Jeff’s legacy and impact will live on long after he departs,” Bezos wrote. “He is simply one of those people without whom Amazon would be completely unrecognizable.”

Amazon declined to make Bezos, Wilke or Clark available to comment.

Wilke steps down in the midst of the coronavirus pandemic, a period when Amazon has wrestled to meet customer expectations and struggled at times to keep its warehouse workers safe. Bezos has called the period “the hardest time we’ve ever faced.”

The executive, though, who has been most responsible for Amazon’s response to the virus has been Clark, who succeeds Wilke. And while the virus continues to create challenges for the company, Clark’s promotion suggests that senior leaders and the board believe he’s proven himself, said a former executive who requested anonymity to maintain a relationship with the company.

The next most senior executive to Bezos is Andy Jassy, the chief executive of Amazon Web Services, the cloud-computing giant that provides the preponderance of the company’s profits. Jassy and Wilke were promoted simultaneously to chief executive of their business units in 2016.

With Wilke now retiring, Jassy appears to be the most likely successor to Bezos, 56, when he eventually leaves, former Amazon executives say. And unlike Wilke, whose expertise was in operations, Jassy is seen as more of a business visionary. He led the creation of Amazon’s cloud business, which seemed an unlikely opportunity at the time, but developed into a key piece of the company’s portfolio.

“The thing that Bezos is that the ops guys aren’t is a dreamer,” the former executive said. “Andy is that too.”

In January, Jassy named Matt Garman as vice president of sales and marketing for the cloud unit, a move seen as succession planning for that business, according to another former executive who requested anonymity because he wasn’t authorized to speak.

Wilke’s purview includes Amazon’s retail, operations, technology and its marketplace and accompanying seller services. He oversaw the integration of Whole Foods Markets, which Amazon acquired in 2017.

During the holiday season each year, Wilke dons flannel shirts, his way to show appreciation of the hard work the warehouse staff puts in as they race to fulfill the surge in orders.

“Heading into my 22nd holiday season at Amazon, I’m once more looking at the flannel shirts that fill my closet rack,” Wilke wrote in his memo. “This holiday with Amazon will be different in many ways. And it will be my last.”

In recent years, Wilke has increasingly worked from Los Angeles, where he and his wife, Liesl, have a home, according to several former executives. Liesl, an author, describes herself on her website as a “Lyme Disease survivor” and writes about taking “sunshine seriously," something that is often in short supply in Seattle in the fall and winter months.

The extended time in Los Angeles has meant that Wilke often did business meetings from Los Angeles, using Amazon’s Chime video conference service.

Wilke joined Amazon in 1999 from AlliedSignal to oversee global operations for the fast-growing e-commerce company. His manufacturing expertise helped Amazon develop its warehouse operations, where packing boxes resembles assembly lines that had been more commonly seen in the process of making products.

Clark, 47, joined Amazon 20 years ago, and has long managed Amazon’s supply chain and delivery businesses. In the last few years, Clark has added oversight of Amazon’s stores, as well as its Prime membership businesses and the company’s marketing operations.

“They’ve been preparing Clark for this for the past few years,” said David Glick, a former Amazon logistics executive who reported to Clark.

Glick, who now serves as chief technology officer at Flexe, which helps retailers warehouse and deliver goods, said Clark has been Wilke’s “mentee” for several years.

“He’s finishing his apprenticeship,” Glick said. “They’ve been loading him with responsibilities and seeing how he rises to the challenge.”