Declan Rice is demanding a buyout clause in any new contract offer from West Ham.
The Daily Star says Rice will only sign a new contract at West Ham if it includes a release clause - which reports suggest could prove a major stumbling block.
Rice, 22, has developed into one of the best midfielders in the Premier League over the past few seasons, as well as become a key member of Gareth Southgate's England squad.
His string of solid displays in the 2020/21 campaign helped West Ham secure Europa League qualification, while he also played a crucial part in England's run to the Euro 2020 final.
As a result, the likes of Chelsea and Manchester United are reportedly desperate to prise him away from the London Stadium.