And McCall is targeting trialists and possible loan signings from England as he looks to further add to his squad.
McFadden joined Motherwell on their pre-season training camp in Spain as he considers an offer to extend his stay at Fir Park while McManus spent the previous week training with the Lanarkshire club.
On McFadden, McCall told MFCTV: "We are quietly optimistic. Unless something comes out of left field on the way back home, I think James is ready.
"A verbal offer has been put to him and it just needs to be written down. We are quietly confident it will be signed when we get back, on Monday or Tuesday."
McFadden's decision could affect that of his Scotland team-mate, Stephen McManus, who was released by Middlesbrough at the end of last season.
"He'll be one we would love to get, but while we have been out here, Stephen has been in at Hibs," said McCall, whose team take on Doncaster tomorrow in South Yorkshire.
"I'm sure he has enjoyed his time there and there have been a couple of English clubs sniffing around him.
"I spoke to Stephen and he'll make his decision over the weekend. So we'll know at the latest Tuesday but possibly Monday."
McCall has brought in John Sutton, Iain Vigurs, Paul Lawson and Gunnar Nielsen and is looking for more arrivals.
"We definitely need another striker and possibly, if we can get one, we need a wide player that can play right or left," he said.
"We would like to get a wide man in. That might be from a team in England on loan. I've got games I'm going to see down south in the next couple of weeks and try to pick up a couple of good youngsters if we can.
"Also, there might be a couple of trialists coming in next week to have a look at.
"I don't like to commit to signing anyone I've not seen play."