The Elland Road club have agreed an undisclosed fee for Scottish international striker McCormack, 24.
Now his Cardiff City team-mate Rae will join him in discussing terms with Simon Grayson.
"Ross is going up to Leeds to have a talk with them and I think (midfielder) Gavin Rae is as well," said Cardiff manager Dave Jones.
"I've said we need to move people out to bring people in and unfortunately they're the ones and maybe one or two more will go as well."
Midfielder Rae made 131 Cardiff appearances, scoring seven goals.
McCormack has netted 33 goals in 88 appearances for the Bluebirds since joining from Motherwell for 110,000 in 2008.
Leeds chairman Ken Bates is angry that details of the proposed move for McCormack were leaked to the media.
"I am rather annoyed that the agent told Sky because its not how we do business," he said. "I can only say we have agreed a fee with Cardiff and we are meeting with his agent this week for discussions."
Manager Grayson, meanwhile, is set to make a decision on the future of Honduran international midfielder Ramon Nunez in the next 48 hours.
Nunez, 24, started his career in the United States but played in Honduras with Club Deportivo Olimpia last season. He has been training with Leeds for nearly three weeks.
Chris Eagles has handed Burnley a major boost by agreeing to sign a new two-year deal.
The 24-year-old has ended speculation linking him with Scottish sides Rangers and Celtic by committing himself to a new contract until June 2012.