LONDON, June 21 - J Sainsbury (SBRY.L), Britain's third-biggest grocer, announced a board reshuffle that underscores its growth ambitions and could secure a successor to CEO Justin King, in the latest round of management changes in the sector.

The supermarket group said on Monday finance director Darren Shapland would become group development director, taking responsibility for new business initiatives convenience stores, banking and property.

He will be replaced as finance director by John Rogers, currently the group's property director.

Trading director Mike Coupe will move to the role of group commercial director, taking on additional responsibility for marketing.

"Sainsbury's today is a bigger business than it has ever been. The business now serves over 19 million customers weekly and has significant growth opportunities by accelerating our space expansion, growing the non food business and developing new channels for our customers," CEO King said in a statement.

Shore Capital analyst Clive Black welcomed the changes as potentially helping to see through the company's ambitious plans.

"We sense that management retention also features in the group's thinking, with some notable roles within the industry still to be filled," he added, pointing to the vacant position of finance director at clothing and foods group Marks & Spencer (MKS.L).

Britain's grocers are undergoing a period of management upheaval, with Terry Leahy announcing his retirement as head of market leader Tesco (TSCO.L), Andy Clarke taking over at Asda (WMT.N) and Dalton Philips at Wm Morrison (MRW.L).

Sainsbury Chairman David Tyler said the management changes were made with the growth potential of the business in mind and not with a view to grooming an internal successor to King, whom he expected to remain with the business for many years.

However, analysts said Sainsbury's would do well to copy the smooth internal succession plan delivered by Tesco and not the more public battle to succeed Stuart Rose as executive chairman at Marks & Spencer.

Sainsbury also said Helen Buck had been appointed as convenience stores director, reporting to Finance Director Shapland.

The changes will take effect on July 19.