The on-loan Burton striker was forced off after just 34 minutes following a heavy collision in Saturday's 2-0 defeat to Bristol Rovers at the Kassam.
Alfie Potter, his replacement last weekend, could get the nod from the start if Richards is ruled out.
Josh Parker looked lively after his substitute appearance and he could be pushing for a start while Lewis Montrose, who made his first home start on Saturday, is likely to be involved again.
Striker Tom Craddock has been missing with a groin injury and Peter Leven is sidelined until April after undergoing knee surgery while Andy Whing returned to the matchday squad after recovering from his ankle injury.
- Sports & Recreation
- Bristol Rovers
- Lewis Montrose