** Shares of Grocery Outlet down ~8% at $15.25 premarket
** Says CEO RJ Sheedy steps down as CEO after almost 2 years in the role
** Former CEO Eric Lindberg to be interim CEO, board to begin process of identifying a permanent CEO
** GO expects preliminary Q3 net sales of $1.1 bln vs analysts' estimates of $1.09 bln - LSEG data
** Co to announce Q3 results on Nov. 5
** Up to Tuesday's close, stock had fallen ~38% YTD
(Reporting by Neil J Kanatt in Bengaluru)
((Neil.JKanatt@thomsonreuters.com;))