Ward limped out of County's win over Leicester on Saturday and he will not add to his four international caps in the World Cup qualifying clashes against Russia and Israel.
The 26-year-old has been restricted to just 20 appearances for the Rams over the last two seasons due to a string of injuries.
Northern Ireland boss Michael O'Neill is also without the suspended Kyle Lafferty for Friday's encounter with Russia at Windsor Park, so Martin Paterson is favourite to start up front with Magennis providing cover.
The versatile 22-year-old came on as a late substitute in last month's friendly against Malta but he was overlooked when O'Neill initially named his squad.
But he returns full of confidence on the back of his two-goal performance in Aberdeen's 4-3 defeat to Celtic on Saturday.