Appiah was set to make his debut for the Italian side on Sunday.
Bologna doctors have confirmed that the midfielder will be out for three weeks, following a hamstring injury he suffered during a midweek friendly.
“The tests by the doctors say I will be out for three weeks which gives me good time to recover before the Nations Cup,” Appiah said.
“It is a difficult time for me but I have the confidence that I will be ready and fit to play for my country in Angola.”
Appiah joined Bologna last month but is yet to make his debut.
“I am totally devastated by the latest events because after such a long absence I was looking forward to returning,” Appiah said.
“I was looking very sharp before this setback now I have to wait on what the doctors will say.
“I put my fate in the hands God. I hope I can recover in time to fulfil my ambitions for my country and club.”
