The centre-back missed the goalless draw with Bradford in midweek after suffering a groin injury in the 2-1 defeat to Gillingham and he is rated as 50/50 to return to action.
The experienced Paul Wotton filled in for the former Aldershot defender and he could deputise again if Charles fails to pass a fitness test.
Bristol City loanee Joe Bryan looks likely to retain his place in the Pilgrims' midfield after an impressive debut just hours after moving from Ashton Gate.
Meanwhile, goalkeeper Rene Gilmartin has returned to full training having been ruled out since early February with a hamstring injury.
Argyle, two points from safety, have failed to score in four of their last five games at Home Park.
- Sports & Recreation
- Paul Wotton