Mackail-Smith missed the 1-0 defeat at the hands of Preston in midweek through illness but he is expected to be fit to return at Selhurst Park as Posh look for a first point of 2010.
Cooper has more problems in midfield however, after winger Chris Whelpdale and central midfielder Josh Simpson both picked up knocks against North End as former boss Darren Ferguson emerged with victory.
The duo are both rated as 50/50 to feature so Paul Coutts and Tommy Rowe could return.
Defender Gabriel Zakuani is still out with a groin injury and Wales international Craig Morgan will sit out the third and final game of his suspension.
