Cole is now battling for his future at Liverpool.
Hislop believes Redknappâ€™s decision to ignore Coleâ€™s off-the-ball development came to everyoneâ€™s disadvantage.
The former Hammers goalkeeper told the Daily Mail: "Harry kind of liked Joe just to express himself, and weâ€™d play around him, or around Joeâ€™s unpredictability.
"Encouraging him to be himself didnâ€™t help him. When you sign him you identify that, talented though he is, when we donâ€™t have the ball heâ€™s got to give us something else.
"Everything about his game on that side, when your team donâ€™t have possession, he simply wasnâ€™t good enough. Harry did not help him in that respect."