Cassano, 31, has been strongly linked with a return to Sampdoria, a club he played for four years before joining AC Milan in 2010.
The 28-year-old Parolo, meanwhile, has attracted the attention of top Serie A clubs having scored six goals in 18 league appearances for Parma this season.
"Antonio will not move from Parma," Donadoni said to Italian TV station Rai Sport. "It is not our intention to sell him.
"Marco has done very well in the first half of the season.
"He has scored six goals from midfield. He could do more, but it's ok. It's normal that the big clubs are interested in him."
Cassano has found the back of the net six times in 17 league appearances for Parma so far.