He told the Daily Record: "I'm not surprised ourselves and Rangers are both looking at Neil and have been linked with trying to sign him.
"He is a guy who could be a big success in the SPL. I can only judge him on the time I spent with him at Palace and he was excellent for us back then.
"Obviously I'm biased, but if I get the chance to speak to Neil I'd tell him to join me at Celtic.
"He'd be a great addition to our squad if we could get him."