Grant saw red for a foul on Morecambe's Andrew Wright during the 2-2 draw between the sides last weekend.
Ainsworth himself is among the list of names who could deputise in Grant's absence, along with Dennis Oli and Junior Morais.
Defender Leon Johnson is a doubt, while Jo Kuffour could play some part after recovering from his ankle injury.
Anthony Stewart (thigh), Danny Foster (knee) and Gary Doherty (back) are still injured, along with striker Ade Azeez (hamstring) who has returned to parent club Charlton for treatment.
Matt Spring serves the second of a three-match ban, while Matt Bloomfield (groin) and Grant Basey (knee) are long-term absentees.