The 25-year-old has been the subject of interest from Fulham this summer, but the City Ground club have made an official approach for the Frenchman.
However, Jackett has said that the bid is below Wolves's valuation of the player.
"They [Forest] have made a bid and it is nowhere near our valuation. Whether they come back or not, I don't know," he told Sky Sports News.
Sako has scored two goals in four appearances for Wolves this season.