Geohaghon followed manager Mark Cooper from Kettering this week and may be given the chance to showcase his huge throw against Gordon Strachan's side.
Posh have not won since beating Scunthorpe a month ago.
New Middlesbrough skipper Gary O'Neil is a doubt for the Coca-Cola Championship trip.
The 26-year-old has been struggling with a groin strain but manager Gordon Strachan is hopeful he will be available after appointing him as his captain in place of defender David Wheater.
Utility man Rhys Williams, who was used at right-back in last weekend's 1-1 draw with Nottingham Forest, is suspended after reaching five bookings for the season.
Central defender Chris Riggott is closing in on a senior return after recovering from a second bout of ankle surgery.
However, Jeremie Aliadiere (ankle), Seb Hines (knee), Caleb Folan (hamstring), Andrew Taylor (ankle ligaments) and Matthew Bates (cruciate ligament) remain on the sidelines.