McFadden made his competitive return in the 73rd minute of Motherwell's SPL match against Dundee United on Tuesday night, but despite some good touches and a couple of blocked shots he could not prevent a 1-0 defeat.
The 29-year-old had only made three substitute appearances for Sunderland previously this season, and McCall tried to temper expectations from the fans, directors and player himself after the game when he warned McFadden did not have a "magic wand".
But McCall is looking to find the balance between helping the former Everton and Birmingham forward regain his match fitness to boost his own attacking prospects, while rewarding the rest of his second-placed side for their form.
McCall, whose team face Ross County in Dingwall on Saturday, said: "I'm not saying he expected miracles for himself but he wants to show what he can do and get involved.
"It will maybe be a case of drip-feeding him at the beginning. He had 20 minutes the other night and we'll see what he gets on Saturday.
"But he has missed a lot of football. Fitness-wise and training-wise he is up to speed and certainly a lot better than he was in the summer, but match-sharpness and game-time he is certainly lacking.
"I think if we started him, we wouldn't get a full 90, but we have a lot of games coming up and parks are very heavy.
"We have just got to try to get him up to match speed and get him going. He is here to play football.
"Having said that, other than the other night where I thought our front players weren't as creative or as dynamic as they have been, he has still got stiff competition to get in the starting 11 because in the last two months I have been really pleased with the performances.
"Everybody wants to play, I have got the likes of Bob McHugh on the bench and Keith Lasley is coming back from suspension and other players who are desperate to be involved, and they all on their own merits deserve to be part of it.
"Faddy is now added to that. The bottom line is, once you get that jersey, it's about trying to keep it. That's a good dilemma for me to have as a manager because I have a lot of options now."
McFadden's signing was hailed by a Motherwell support to whom he has remained a hero since his move to Everton 10 years ago.
But McCall is eager to stress that McFadden is at Fir Park as a team player.
The Motherwell boss said: "I don't think the squad needed a lift because we have done well this season, but obviously it's been a great lift for the supporters. They remember the Faddy of old.
"And he has been a great addition to the dressing room and the squad.
"We are a tight-knit squad and everyone is pushing in the same direction and everyone is fighting for places.
"It's not the James McFadden show, he is part of a squad and he is part of a team and he is happy to be that.
"I'm sure once he gets up to speed he will be a great acquisition for us and it will do well for him and do well for Motherwell."
Motherwell face a Ross County side who have kept their opponents from scoring in three of their last four games, a return to their early-season form when a goalless opening day draw with Motherwell was the first of five clean sheets from six SPL matches.
McCall said: "I'll be looking for a better attacking show than the other night against Dundee United and from the last time we were up there."