The England international has hit five goals so far and netted a last-gasp equaliser to hold Arsenal to a draw last Saturday.
"He's a big threat, probably their biggest to us to be honest," he told liverpoolfc.tv.
"Wherever he has been he has always scored goals. He does what he does best and he is a goalscorer.
"Like most strikers they can be quiet for 80 minutes then come up with a goal like he did against Arsenal last week.
"For me he has been one of the most underrated strikers around for a long time. I remember when Charlton signed him years ago for £2million and it was one of the best buys ever. I think he's a great player.
"They also have their record signing Asamoah Gyan who played in the World Cup. He looked decent in South Africa and I'm sure he will be a good player for them."