Rangers owner Craig Whyte has insisted that goalkeeper Allan McGregor is not for sale.
Aston Villa have been linked with a move for the Scotland international, with new boss Alex McLeish seeking a replacement for Brad Friedel, who recently joined Tottenham.
And talk of a swap deal has been mentioned, with defender Carlos Cuellar said to be open to a return to Rangers.
But Whyte told the Daily Record: "I've said that McGregor is not for sale. We haven't been approached by anyone about him so far.
"As far as Cuellar is concerned we have made a formal offer. We are actively discussing it."
Whyte confirmed his intention to bolster the squad, adding: "We would like to get some signings in as soon as possible but don't want to bring in the wrong players.
"We have spoken about bringing in five or six new players and that is probably the required amount.
"With Scottish clubs the price always seems to go up when they are dealing with Rangers or Celtic. But we are not going to overpay. We won't be pushovers to deal with."
Whyte was referring to Dundee United striker David Goodwillie, who is a target of Gers although a fee has yet to be agreed with his current club.
"I would say that price is too steep but I'm sure there are conversations to be had," said Whyte.
"It's a learning curve as I've never run a club before but dealing with transfers is not a lot different from other business deals."