Home boss Darren Ferguson has striker Kyle Vassell back in contention for a place in his squad after a toe injury as they host the Millers, looking to close the 8 point gap between the sides.
After a 2-0 win over play-off hopefuls MK Dons last time out, Ferguson will be hoping his side can build some momentum for the final run in.
Influential midfielder Danny Swanson also returns after a two match ban.
The Millers boss Steve Evans celebrates 100 games in charge at the New York Stadium as his side travel to London Road.
Mark Bradley and Wes Thomas are the only confirmed absentees at the moment. Bradley is out for the season and undergoes knee surgery shortly, whilst Thomas has aggravated a thigh problem.
Tom Hitchcock or Haris Vuckic may deputise, or there is a possibility of top scorer Kieran Agard partnering Alex Revell with last weeks late goal hero Nicky Adams coming into the starting line up.
Agard is one of three Posh old boys returning to their former club, along with captain Craig Morgan and dynamic midfielder Lee Frecklington.