Former Everton and Birmingham forward McFadden, a free agent since his short-term deal at Fir Park expired in May, spent last week training with Motherwell in Spain.
However the 30-year-old did not play in Saturday's goalless draw with Doncaster in their pre-season friendly at the Keepmoat Stadium.
McCall told MFC TV: "The most James would have got is the last 15 minutes and would it have been worth it?
"He has not missed a session since he joined us and has worked hard.
"He'll be in on Monday morning hopefully to get things tied up and look to play a part in the game on Tuesday against Newcastle."
McCall remains hopeful of securing a deal for another Scotland international, Stephen McManus, who spent last week with Hibernian after training with Motherwell the previous week.