The 28-year-old forward joined Hearts last summer from Belgian outfit Beerschot and impressed with his performances.
Shankland scored 24 times for Hearts in 37 league appearances for the club and helped them finish fourth in the table.
And his performances last season have attracted interest from the Saudi Pro League and Championship.
It has been claimed that the Jambos have received enquiries from Saudi Arabia and Championship outfits.
Hearts are not keen on selling Shankland, who has two more years left on his deal with the Tynecastle side.
However, it is suggested that an offer of £3m could test their resolve to keep the Scotland international at the club.
Shankland has also begun this season in an impressive manner and has scored two goals in three matches for Hearts so far.
