The Cameroon international is set to arrive at Anfield in the summer, with Liverpool having moved quickly to secure him on a free transfer from German side Schalke.
Jurgen Klopp will be hoping that he can come in and seriously improve what has been a defence that has once again struggled this season.
And Molby has predicted that one of Martin Skrtel, Mamadou Sakho and Dejan Lovren will be moved on when he does finally arrive at the club.
“The imminent arrival of Joel Matip from Schalke in the summer will almost certainly spell trouble for one centre-back at Liverpool,” he told the Liverpool Echo.
“You have to assume Matip will be the number one choice. That's why Jurgen Klopp has bought him. The question now is who Klopp will prefer alongside the new signing.”
“He'll have a good idea, and with our squad already well blessed in terms of centre-back numbers, I'd not be surprised if one of Mamadou Sakho, Dejan Lovren and Martin Skrtel are moved on.”
Of those three, it would surely be Lovren that would be making an exit from the club.
The defender has struggled to live up to the big price tag that accompanied his move from Southampton, with his first season under Brendan Rodgers a complete disaster.
He has not really improved since then either, with Skrtel and Sakho both preferred when everyone is full fit, making him the prime candidate for the chop should things pan out as Molby predicts.