Former Lincoln and Peterborough midfielder Gain will sit out the final game of his three-match ban following his sending-off at Oldham on February 5.
Winger Danny Green returned from a suspension of his own in the defeat to Walsall last week, while defender Scott Doe is available after shaking off an arm injury.
Striker Josh Scott is out for the rest of the season with a blood clot and central defender Will Antwi overstretched in training this week and hurt his groin.
He will be given a late fitness test but is expected to be passed fit.
Source: PA
Source: PA