The former Northampton centre back suffered a recurrence of a groin injury that he suffered earlier this month in the 2-0 win at Southend.
Paul Wotton replaced Charles in the first half of that vital victory on Tuesday night and he could get the nod from the start.
Striker Warren Feeney, who picked up an ankle injury in Sheridan's first match in charge in mid-January, has returned to training along with homegrown defender Curtis Nelson. The youngster had been sidelined by a persistent groin problem since late January.
Captain Conor Hourihane heads into this match on nine yellow cards, one away from two-game suspension.
Argyle are now two points clear of the relegation zone after suffering just one defeat in their last six games.