The Israel international has been looking for a club since being released by Chelsea and has been linked with a possible move to join Championship side QPR, but he could now return to Spain where he previously had a three-year stint with Racing Santander.
However, as the 33-year-old holds a non-EU passport, Casado confirmed one of the club's three non-EU players would have to be moved out to make space for Benayoun.
"We are in contact with some interesting players. One of them is Benayoun, but he's not already signed," Casado told La Opinion De Malaga.
"He is a non-EU player and if he comes, one of the other non-EU players, Weligton, [Roberto] Chen or [Pedro] Morales, should leave."
Malaga have had an inauspicious start to the season, taking 13 points from as many La Liga fixtures, a return that leaves Bernd Schuster's men in 14th position.
They resume their league campaign at home to Athletic Bilbao after the international break.