McCann was a second-half substitute during last weekend's defeat at Tranmere after featuring for Northern Ireland on the Friday night but will start as Posh look to get back to winning ways.
Winger Arron Davies is set to be out for up to three weeks after picking up a hamstring injury against Tranmere.
Chris Whelpdale is fit again after a thigh injury but winger Nathaniel Mendez-Laing will have a late fitness test on his knee injury.
Full-back Mark Little is beginning a six-week lay-off after injuring his knee and midfielder Lee Frecklington (knee) remains sidelined.
Defender Gabriel Zakuani is back to full fitness after his summer groin operation but is expected to be on the bench.