Speculation has surfaced that both players could leave Elland Road during the transfer window after impressing for the Whites last season.
Their departures would strike a blow to the Yorkshire club following the exits of regulars Neil Kilkenny and Bradley Johnson and goalkeeper Kasper Schmeichel's move to Leicester.
The club rejected an offer for Snodgrass from promoted Norwich last month, while Gradel is reportedly a target of Premier League Fulham and Championship rivals West Ham.
Ivorian winger Gradel, who scored 18 Championship goals last term, is out of contract with Leeds in 12 months' time, while fellow forward Snodgrass has two years remaining on his deal.
Grayson has moved to allay fears over the pair's future, insisting they are both central to his plans for the forthcoming campaign.
Asked if he was confident of keeping them at the club, he told the Yorkshire Evening Post: "Definitely. All our work will be done around the players we've got.
"Obviously if somebody offers money that you think is too good to turn down then we'd go out and replace them.
"It's not like any money that comes in will be left in the bank - we'll be going out to spend it straight away.
"But I'm envisaging that both players and every other player at the club will still be here at the start of the season."