Asda is poised to unveil Andy Clarke, the grocer's chief operating officer, as its new chief executive next week, as it emerged another leading internal candidate has quit this week.
Darren Blackhurst, Asda's chief merchandising officer, had been tipped for the top job but left the company earlier this week after "discussions about his future".
The supermarket chain's likely hiring of Mr Clarke as chief executive follows the decision by Andy Bond last month to step down and become part-time chairman.
The new chief executive would take the helm at a tricky time for Asda, whose sales have recently fallen behind Tesco, Sainsbury's and Morrisons, according to recent industry data.
Asda, which employs 4,500 people in Northern Ireland, declined to comment on its new chief executive yesterday.
Mr Clarke is understood to be highly regarded by Walmart and was promoted to chief operating officer in January 2009.
Mr Clarke had returned to Asda as retail director in 2005 after a four year absence which had included stints as managing director of Iceland, the frozen food specialist, and chief operations director at Matalan, the discount fashion chain.
Previously, he had been at Asda for nine years between 1992 and 2001 and his last role had been retail director. Two other potential internal candidates for the top job at Asda - Judith McKenna, the grocer's chief financial officer, and David Cheesewright, the chief executive of Walmart Canada - recently ruled themselves out of the running.
The latest data from Kantar Worldpanel suggests Asda's sales growth has fallen behind its big three rivals. For the 12 weeks to April 18 2010, Asda delivered sales growth of 2.5%, which was behind Morrisons' 6.6 per cent, Tesco's 3.7 % and Sainsbury's 4.1%.