He has made just one senior appearance, coming on as sub in an FA Cup clash at Millwall last season.
Saints boss Nigel Adkins has included the England Under-17 defender in his first-team squad for pre-season training.
A source told the Daily Star: "If Chelsea, or any other team, make an offer they are wasting their time. He is not for sale, and is staying here.
"It has been suggested he is not under contract, but he agreed professional terms back in December 2010, and his three-year contract begins on his 17th birthday."