McFadden rejoined Motherwell in February on a short-term contract until the end of the season, having played for the club earlier in his career.
It had been unclear whether he would look to move on in the summer, but he has travelled with McCall's squad to their pre-season training camp in Spain and talks now need to take place about a possible new agreement.
"I'm cautiously optimistic James will join us. I'm pleased he's here. I'm hopeful we can get something sorted out when we get back," McCall said in the Daily Record.
"I said if he wanted to return and be involved in European games, he had to be here with us.
"I'd think it would be a similar situation to last season when someone pays his wages.
"The offer has been made, they just need to sit down and tie up the length of contract."