The 33-year-old has played just 14 minutes of Premier League football for the Hammers this season, while he has appeared on just 13 occasions for the club since arriving in the summer of 2018.
Sanchez was an unused substitute during West Ham's 3-2 home loss to Newcastle United on Saturday, and according to Football Insider, the Colombian's days at the club are numbered.
The report claims that the London outfit are prepared to sell the experienced midfielder at the start of 2020 should a club be willing to meet their asking price of around £3.5m.
Sanchez, who has been capped on 88 occasions by Colombia, will see his current deal at the London Stadium expire next summer.
A poor run of form has seen Manuel Pellegrini's side fail to win any of their last five Premier League matches, which has left them in 12th position in the table.