Robin Whitbread, 44, director of grocery, and Bob Cooper, 46, director of trading, have been lined up for additional influence and responsibility as part of their grooming for the top.
Mr Vyner, who is also deputy chairman, may start to relinquish some day- to-day control down the line, given the extra work generated by the absorption of Texas and hotly tipped plans to acquire the whole of US chain Giant, in which it holds a 16 per cent stake. In a similar shift of power last month, Tesco promoted Terry Leahy from marketing director to deputy managing director. Some also expect Tesco finance and distribution director David Reid to be moved up, paving the way for an eventual joint succession to chairman and chief executive Sir Ian MacLaurin.
Mr Vyner's sales and marketing remit at Sainsbury was added to last year when David Quarmby - with whom he shares the managing director role - moved from store operations to focus solely on long-term strategy and planning. "Vyner has built himself quite a fiefdom there, which is likely to need two people to carry on," said one analyst.
Sainsbury could announce the moves at its results meeting in May, but the changes are just as likely to be kept low-key and to roll out over time.
Mr Whitbread and Mr Cooper are among the younger members of the 18-strong Sainsbury board. Mr Cooper joined the company in 1975, rising to board director responsible for buying in 1988. Mr Whitbread, recognised as the more political of the two, began his Sainsbury career - which included a spell as PA to Lord Sainsbury - as a retail management trainee in 1969. He was appointed as departmental director in 1983, then as the company's first main board marketing director in 1990.Reuse content