Molby reckons Gerrard is a massive figure on Merseyside but his failure to help steer the club to a top-flight crown means he falls short.
He told the Daily Star Sunday: "It's impossible for me to say he is the best Liverpool player ever. I think he would have to be in anyone's top three or five but there are others with a claim to the title - for a long time Kenny Dalglish was acknowledged as the best.
"I think a better way of putting it is that Gerrard is the most important. He means more to the team than anyone in Liverpool's history.
"But when we look back at his career, some people might talk about a lack of fulfilment.
"He hasn't won a league title and there's no real prospect of that changing before he retires."