The 25-year-old rejected a move to fellow Championship side Leicester City last week.
Saunders now hopes that Sharp signs a new deal at the Keepmoat Stadium.
"Nothing's changed since last week," said Saunders. "He's indicated that he wants to stay, so, unless somebody comes in, which they could do at any minute, as far as I'm concerned we prepare for Saturday.
"I think he's indicated he wants to stay until the end of the season and the new contract is coming into play.
"I think Billy probably thinks if it's not right to go to Leicester and he bangs some goals in for us between now and the end of the season then he's going to have a lot more options."
Sharp has scored 10 goals in 19 Championship games this season.