Crystal Palace boss George Burley wants to bring in a left-back before Saturday's Championship opener against Leicester.
New signing David Wright has emerged as an injury doubt due to a hamstring problem, leaving youngster Nathaniel Clyne as the club's only recognised full-back.
"We are hoping to tie up a deal for a left-back," said Burley.
"We have been working hard all week to strengthen the squad as we are very short of numbers."
Burley has also confirmed that winger Sean Scannell will be out for "five to six months" following knee surgery.