Exeter have been boosted in their unlikely pursuit of League One survival by the return from injury of Scot Bennett and Jonathan Fortune.
The two defenders have been suffering from hamstring problems of late but will be available to Grecians manager Paul Tisdale on Saturday.
The Devon club must win to avoid relegation but they will have to do so without striker Lauri Dalla Valle, who has returned to parent club Fulham at the end of his loan spell.
Danny Coles (fractured spine) and Richard Duffy (groin) are also set to miss out for Exeter as they continue to make their way back to full fitness.
Walsall will be without Lee Beevers for their crunch trip but manager Dean Smith is boosted by the return of like-for-like replacement Richard Taundry.
Right-back Beevers was shown red for a second bookable offence during injury time in last weekend's disappointing 1-0 home defeat to Tranmere, resulting in a one-match suspension at St James' Park.
But Taundry, who missed the clash due to a recurrence of his troublesome hamstring strain, played an hour for the club's reserves in midweek and will be in contention, along with Darryl Westlake, to replace Beevers.
Midfielder Peterlin also returns to the fold after an ankle injury having played the full 90 minutes for the second string.
Striker Will Grigg pushed his claims for involvement against the Grecians by bagging four goals in the reserves' 6-3 win over Burton.
Victory for the Saddlers would relegate Exeter and potentially go a long way to securing their own League One future, with fourth-bottom Wycombe away to runaway leaders Charlton.
