Colin Holmes is back at Tesco after an eight-month sabbatical.
Holmes left his post of chief executive of Tesco's convenience business last April to "spend more time with his family and do charity work".
He does not yet have an official position although an announcement is expected shortly.
"Colin is now back at Tesco and attending board meetings," said a spokesman for Tesco. "At the moment he is going into stores to bring himself back up to speed."
Holmes has held various positions at Tesco over the course of 20 years, and has been tipped in the past as a possible successor to chief executive Sir Terry Leahy.
Before taking the helm at Tesco's convenience business, Holmes was CEO of T&S Stores, the convenience store chain that Tesco took over in 2003.
Prior to that he was operations director for superstores central and has held other senior roles in finance and retail roles at Tesco.