McCall insists he has not had any serious discussions with McFadden, who has been training with his former club after leaving Sunderland, despite mounting speculation the 29-year-old is about to sign a deal with the club where he launched his career.
But, amid what McCall termed the "euphoria" surrounding a possible reutrn, he admits he will now speak to him after tomorrow's Clydesdale Bank Premier League clash against Dundee United.
McCall said: "The latest on James is that he has been in training again this morning and is going to come back tomorrow.
"Hand on my heart, as I keep reiterating, I have not spoken to James.
"The only thing I have said to James in the last four or five days is 'give me 20 press-ups' because he keeps doing the wrong drills.
"I'm fully focused on tomorrow's game. But obviously with everyone discussing it now, things will have to come to a head and I'll have to speak to James, but it certainly won't be before Tuesday night's game.
"In that time, James might have moved on and got fixed up with a club.
"The arrangement was for him to come in and keep his fitness up, which he has been doing. But I will have to discuss matters, which will be on Wednesday."
While McCall has not had contract talks with McFadden, it is understood the club are optimistic of persuading the former Everton player to sign until the end of the season, and began initial attempts to do so before Saturday's 3-0 victory over Inverness.
McCall was keen to sign him following his first training stint with the club earlier in the season but McFadden, who scored 32 goals for Motherwell as a teenager, did not agree a deal with chief executive Leeann Dempster.
Having only made three substitute appearances at Sunderland, and with a subsequent move to Nottingham Forest breaking down when Alex McLeish left the City Ground, McFadden might be more inclined to sign this time, although he is believed to have other options.
McCall added: "Before he left to go to Sunderland, there was an offer made to James and that would probably stand again.
"But at the moment I'm finding it hard to get two or three good players in my team.
"Bob McHugh is scoring goals for fun in the under-20s, Keith Lasley is out of the team and Stuart Carswell has come in and done well.
"Jamie Murphy departed and obviously we brought Kallum Higginbotham in to fill that space and that's the budget we had.
"It wouldn't surprise me if James said he was looking at a short-term deal and would there be any finance there, then I'm sure the club would do anything in its power to make that happen.
"But there's still a long way to go. I haven't spoken to James and I don't know his feelings."
McCall is set to pledge his own future to the club in the next week by extending his contract beyond the summer.
And he hopes that will kick-start contract talks with a number of players whose deals expire at the end of the season, including Darren Randolph, Chris Humphrey, Nicky Law and Michael Higdon.
"We'll get the game out the way and have a couple of days before we go to Ross County on Friday, and no doubt my representative will be in talking to the club, but I don't envisage any problems," McCall said.
"I have spoken to most of the agents of players whose contracts are going to be up, and have got a guide of where they see themselves.
"I would think in the coming weeks we would be at a stage where we will be offering contracts to most of the players.
"Whether we get definite answers will be a different matter, but I would like to think there will be a few that are signing on."
Another factor in keeping his team together will be their final placing and whether they qualify for Europe again.
Motherwell will move five points clear in second place if they beat United tomorrow, and 10 points ahead of the Tayside club.
McCall said: "What can be decided in the next couple of weeks is if we will be in the top six.
"If we win our next couple then it will give us a real good guide.
"Obviously the team in 11th could quite easily finish in the to six or even the top two.
"It's all about consistency but we have been in a good run of form."