Walmart is losing the leader of its nascent ads business, Stefanie Jay, VP and general manager of Walmart Media Group, and named Rich Lehrfeld, senior VP of marketing, to take her place in the interim.

The media group is a branch within the retail giant that is is responsible for developing its ads platform. “Rich has a deep background in media and relationships within the industry that will prove instrumental as we continue to grow,” Janey Whiteside, Walmart’s chief customer officer, wrote in an internal memo today. 

Walmart declined to comment beyond the memo that was sent to staff about Jay’s departure, including about where she is going. The memo says Walmart will conduct an external search to potentially re-fill the Walmart Media Group leader position. Lehrfeld reports to Whiteside.

Jay had been with Walmart since 2015, and has been a driving force behind the media and advertising strategy. Walmart Media Group has been a major focus for the retailer as it tries to build advertising infrastructure that can compete in the growing e-commerce space. Amazon has led the way showing how major shopping destinations can turn into lucrative advertising opportunities, a playbook being followed by Walmart, CVS, Target, Kroger and others.

“Under [Jay’s] leadership, the team has delivered on the vision of customer-centric advertising, self-serve and automation for advertisers and driven strong revenue growth,” Whiteside wrote.

Last year, Walmart began a major reorganization within its media operations, cutting ties with WPP’s Triad, an agency that handled its advertising relationships. Since then, Walmart has been building its own programmatic ad platform and in-house team.

Also, Walmart has been exploring new kinds of marketing and media opportunities with an interest in the world of social media. The retailer was even in the hunt to acquire a piece of Chinese-based TikTok, a deal that was brewing over the summer but has not come to fruition. Still, Walmart is clearly interested in forming relationships with new digital partners.

Lehrfeld has been with Walmart for a little over a year, and before that spent about two decades at American Express. Lehrfeld leads “brand strategy and marketing, advertising, communications, media planning and buying, social media, brand and talent partnerships and the in-house creative agency,” according to his LinkedIn page.

Lehrfeld also has account experience from his early professional years at Wieden+Kennedy and Ogilvy.

Walmart did not say whether a new executive would assume Lehrfeld’s official duties as senior VP of marketing at Walmart Media Group. The memo said a team of five people from Walmart Media Group’s leadership—covering strategy, operations, sales and partnerships, B-to-B marketing and analytics—would now report directly to Lehrfeld.  Lehrfeld’s current marketing team will report directly to William White, chief marketing officer.