The Gunners have already opened talks with Feyenoord over a potential £23m deal for Kokcu .
But Van Hooijdonk says: “Of course it is a lot of money for a 'potential purchase'.
“With all due respect, everyone sees that he is a talent, but he has not played 34 games in Feyenoord's first-team as a supporting man.
“His quality is, among other things, his scoring ability, but we have seen that too little this season. He can become a very good player, but I don't think 26 million is worth it yet.
“I think it would be a shame to see such a player go to Arsenal; he hasn't even had one super season yet."