McFadden is currently training with Motherwell after leaving Sunderland in January and seeing a potential move to Nottingham Forest fall through.
Sunderland have not ruled out another short-term contract for the 29-year-old, with Black wary of upsetting Motherwell's squad with the addition of McFadden.
"It only makes sense if you have the finances to do it," said Black in the Daily Record regarding a deal for McFadden, who originally left Motherwell for Everton in 2003.
"James is a top player and an experienced international but I don't know if the finances would allow us to offer him a deal.
"We have a number of players out of contract in the summer and I'd love to be able to tie these guys up for next year.
"We would like to keep everybody but due to financial restraints, or other clubs coming in offering better money, that may not be possible.
"Whether James would even be interested in playing for us, I don't know. I'm led to believe all he is looking for is training facilities.
"It's a similar situation to a few months back when he came to get himself fit and earn a move to Sunderland. He's a local lad and we are happy to have him on board. That's as far as it goes."