Van Dijk will be at Anfield with Southampton tomorrow.
Writing for the Liverpool Echo, Molby stated: "Liverpool fans will be looking forward to Virgil van Dijk but both full-backs in Ryan Bertrand and Cedric Soares are excellent players. They've got good protection in front as well.
"It would be almost ridiculous if Liverpool didn't go back in for van Dijk in January. I'd be amazed if they didn't.
"The problem for him is that everyone will know the fee will be £60million-plus to buy him and he'll be judged on that, not whether he looks a good player or not.
"But I don't think many Liverpool fans will come away thinking he wouldn't be a good addition to the team.
"A good showing from him might ease any doubts among the club's owners that he is worth the money that's being talked about."