McCormack has been the subject of several offers from Championship rivals Middlesbrough this summer, but Leeds have been determined to keep the 27-year-old.
The Scotland international has enjoyed an impressive start to the season and has scored four goals in six appearances in all competitions.
He has previously stated that he is not looking to leave Elland Road and is now poised to finalise an extension to stay with Leeds until 2017.
Speaking earlier this month, McCormack said: "If I'm going to go it's going to be their (the club's) decision. It's not going to be my decision.
"Not once have I asked for a transfer and I won't force through a move.
"But if there's an issue with the club and they need me to move on for money, sometimes in life you do things that you don't want to do.
"I'm firmly happy here and I'm settled in the area. It's always nice when other clubs are putting in offers for you but as I've said numerous times, I'm happy.
"This is a massive club and I'm really honoured to be here."