Sam Rents stands by at left-back, with fellow youngster Tommy Elphick continuing in the centre of defence.
Jake Robinson is in line for a return on the right of midfield, having missed the first two games of the season with damaged ankle ligaments, although he may struggle to oust Tommy Fraser.
And fringe midfielder Doug Loft is also available to manager Dean Wilkins after recovering from a knee injury.
Centre-half Adam Hinshelwood is expected back in training on Monday following a lengthy absence with knee-ligament damage.
Northampton have an injury doubt over in-form striker Andy Kirk.
The former Northern Ireland international was taken off the transfer list in the summer and has repaid Gray's faith in him with two goals in the Cobblers' opening two fixtures this season.
But Kirk is struggling with a slight groin strain picked up in the 2-0 Carling Cup win over Millwall and Colin Larkin is on standby to partner Poul Hubertz in attack.
Other than Kirk, Gray's only concern remains midfielder Giles Coke, who is still at least a fortnight away from a debut as he continues his rehabilitation from a serious knee injury sustained in January with former club Mansfield.
Sporting Life