Jones missed the midweek draw at Charlton due to a dead leg, while a knee injury has kept Law out of City's last three matches.
Alex Gilliead, who injured his hamstring during the recent victory at Coventry City, has returned to parent club Newcastle United for further assessment.
Early estimates suggest the loanee winger could be ruled out for at least the next four weeks.
McCall said: "It is probably too soon to say for certain about those two (Alex Jones and Nicky Law).
"Nicky has continued to do some work with the physios and looked fine. Jonesey joined in with a training session but perhaps didn't look 100%.
"It would obviously be great to have one, or ideally both, available to us on Saturday but I would say they are both '50-50' at this stage.
"We will keep monitoring them and then make a call on Friday.
"He (Alex Gilliead) has gone back up to Newcastle for a MRI scan and an opportunity for their doctor to have a look at him.
"He will then return back down to us to begin his treatment. Unfortunately, it seems the tear in his hamstring is slightly bigger than we first thought.
"We will know more in the next 24-48 hours or so once we've received the results of the MRI scan.
"He is looking at probably at least a month out though.
"That will mean we cannot think about Alex in terms of selection for the time being but hopefully he will be back to play a part at the end of the season."