Middlesbrough have rejected an offer for the defender but Rangers are hoping to sign him before Saturday's match against Reading.
Davies, who impressed during his recent loan spell, is keen to make the move and Boro are willing to let him go.
But Ipswich and Wigan are also interested.
Meanwhile, Dean Sturridge's proposed move to Loftus Road has hit complications.
A loan deal had been agreed and the Wolves striker was due to play for Rangers in a reserve match on Tuesday.