Marshall limped off towards the end of the goalless draw with the Addicks while McCall revealed after the game that Law had picked up a strain during the encounter at the Northern Commercials Stadium.
Speaking ahead of the Walsall match, McCall says that the duo's recovery means that Billy Clarke remains the only player currently on City's injury list.
McCall said: "They are both doing fine now.
"Lawsy (Nicky Law) had a couple of days of rest at the start of the week and he is fine now.
"Marshy (Mark Marshall) is the same really.
"Like last weekend, there is only Billy Clarke out for this Saturday.
"We expect him to be out for another ten days or so, maybe two weeks with his calf.
"Other than Billy, the group is all fit and raring to go."