The UK's second-largest supermarket chain said it was consulting on a series of measures that would mainly affect human resources and payroll staff - freeing up cash for the continuing price war with rivals.
The FTSE 100 company wants to remove all HR and payroll clerk roles from in-store completely - hitting around 1,400 people.
It said 600 further roles were under threat from a restructuring that would consolidate HR and other support roles across its grocery chain, Argos and Sainsbury's Bank.
A spokesman said: "The UK grocery market is changing at a rapid pace and it's crucial that we transform the way we operate to meet future challenges and continue to provide customers with best in class service.
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"Following a comprehensive review, we are proposing some updates to our HR structures and systems, as well as changes to a number of other support roles, subject to consultation.
"This has been a difficult decision and we appreciate that this will be a tough time for those colleagues affected by the changes. We will support them in any way we can."
The company, which currently employs just under 200,000 people across its businesses, confirmed the cost-cutting plan after the markets had closed for the day.
The shake-up by Sainsbury's, which took over Argos last year, is part of a previously announced £500m efficiency drive aimed at allowing the company to invest more in its customer proposition.
The most recent industry data, published by Kantar Worldpanel, showed Sainsbury's market share had fallen to 15.8% in the 12 weeks to 8 October from 16% a year ago.
The value of sales for the sector was 3.1% up, with Sainsbury's showing growth of 1.9%.
The report painted a fairly rosy picture for the industry as spending on essentials shows little sign of winding down.
Wider retail sales have come under pressure from the Brexit-linked squeeze on household budgets as inflation outpaces wage growth.