Bertrand came through the ranks at Stamford Bridge as a youngster before completing a permanent £10million move to Southampton in February 2015 in search of more regular game-time.
The 27-year-old has since established himself as one of the most consistent left-backs in the Premier League and he’s earned 15 caps for England.
Sportsmail suggest Antonio Conte is scouring the market for defensive reinforcements ahead of the 2017/18 campaign and Bertrand is on the Italian’s wishlist.
It’s understood the Blues may have to shell out at least double the amount they sold him for back in 2015 but the league leaders remain interested.
Chelsea have a history of signing former players, with both Nemanja Matic and David Luiz returning to Stamford Bridge in recent seasons.
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Bertrand’s Southampton team-mate Virgil van Dijk is also being heavily linked with a move to Chelsea this summer.