Ward has rejoined the Reds on loan from Norwich for the remainder of the season and should replace captain Danny Collins, who must serve a one-match suspension after his red card in the FA Cup defeat to Oldham last weekend.
Alex McLeish, looking for his first win as Forest boss against Posh, will also include Chile international defender Gonzalo Jara Reyes in his squad after singing the right-back on loan from West Brom for the remainder of the season.
The Scot has also bolstered his goalkeeping options by recalling Karl Darlow from his loan spell at Walsall, and the 22-year-old will make his full league debut for Forest after long-serving number one Lee Camp was told he is free to find another club.
On-loan centre-half Daniel Ayala continues to struggle with a hamstring injury and McLeish will be without the Spaniard for the rest of the month.
"The prognosis for him is that he will be out for three or four weeks. That is not what we need right now," said McLeish, who will check on Andy Reid after the winger limped off against the Latics with a groin problem.
Meanwhile, midfielder Adlene Guedioura is away on African Nations Cup duty with Algeria.