Parkes is suspended after picking up his 10th yellow card of the season in the 4-2 win over Dagenham on Monday and that means a first start for Port Vale loanee Clayton McDonald.
They will also be without influential midfielder John-Joe O'Toole who has returned to Colchester after the end of his loan spell.
Goalkeeper Steve Mildenhall will return to training in the build-up to the match and is expected to play after missing Monday's clash with an ankle injury sustained during the warm-up.
John Ward says his players must aim to finish the season inside the top half of the npower League Two table, a real achievement considering Rovers were bottom on Boxing Day.
- Sports & Recreation
- Steve Mildenhall