West Ham United are reportedly concerned that Andy Carroll will try to force through a January move to Chelsea.
The reigning Premier League champions are believed to be keen on signing the former Liverpool forward.
In the past few years the 29-year-old has struggled with injuries, and this season he has been restricted to just eight starts in all competitions.
According to The Telegraph, the Hammers want their striker to stay put, but fear that he may have other ideas after learning of Chelsea's interest.
Blues manager Antonio Conte is said to have been impressed by Carroll's aerial ability, which the Italian believes could be an asset during the closing stages of the season.
The England international has scored two goals in 12 top-flight outings this season.