Dive Brief:

• Walmart's U.K, grocery unit Asda has tapped Rob McWilliam as a part-time strategic advisor to CEO Roger Burnley, Bloomberg reports. Before that, McWilliam served as Amazon U.K.'s vice president of finance, according to his LinkedIn page, (which doesn't list any current Asda role).

• It's a return for McWilliam, who served in various roles at Asda from 1997 to 2013, when he jumped to Amazon, according to his LinkedIn profile. Requests for confirmation to Asda and Walmart weren't immediately returned to Retail Dive.

• Burnley himself is new to the CEO position. Walmart last year began shuffling that post, announcing in June 2016 that Sean Clarke, who had been president/CEO of Walmart China, would replace Andy Clarke. Clarke had hinted then that Burnley would be his likely successor, but Burnely was named deputy CEO and took over as Asda chief operating officer.

Dive Insight:

McWilliam's return to Asda comes as the grocer continues to struggle amid a brutal grocery war going on in Britain, with the likes of Sainsbury, Tesco and Morrisons also struggling to hold onto their customers. Asda has also seen sales fall as more shoppers in the U.K. head to low-price German rivals Aldi and Lidl.

"[Asda] was the greatest division a few years ago," Howard Davidowitz, chairman of New York retail consulting and investment banking firm Davidowitz & Associates, told Retail Dive last year. "Then Aldi and Lidl went across England, and now Asda is doing very badly."

In 2015, Asda, a Walmart-owned U.K. retail chain with more than 600 stores, announced a turnaround dubbed "project renewal" to reverse those fortunes. That included plans to cut prices, accelerate improvements to its stores and halt plans for "click-and-collect" sites. Walmart in the past has made clear that it would start to play rough in the pricing war, sacrificing profits in a bid to protect market share.

Last year, though, Amazon also said it would be more assertive in the space, inking a deal with U.K. supermarket Morrisons to offer packaged and fresh and frozen goods and deliver them to customers in as little as an hour. That deal boosts Amazon's operations in the U.K. and promises to lift Morrisons e-commerce sales, which have lagged behind other U.K. grocery e-commerce. 

The price war that has decimated the grocery market in the U.K. could be emerging in the U.S. as well, now that Lidl has arrived and Aldi has grown. Aldi is in the midst of what it calls an accelerated expansion plan that will enlarge its U.S. footprint to nearly 2,000 stores by the end of 2018, an increase of almost 50% in five years.