Rovers have had two bids for the 23-year-old, from Tottenham and Aston Villa, but neither has come anywhere close to the price Blackburn believe Bentley is worth.
Williams said: "We have received two bids but neither have come anywhere close to our valuation which is based in line with how we see the market.
"We don't want to lose David but if we do get a bid that meets our valuation then ultimately it comes down to a football decision by Paul (Ince).
"David is one year into a four-year contract but he told us when Mark Hughes was here that he wanted a move so this doesn't come as a shock to us."