Caulker previously played for Brendan Rodgers during a loan spell at Swansea City and is said to be keen to work with the Northern Irishman again.
The 22-year-old reportedly has a release clause of £8million, providing a much cheaper - and younger - alternative to Liverpool target Dejan Lovren. But how do his stats compare to the Reds' current centre-backs?
|Team||Pos||Tackles Won / app||Interceptions Won / app||Effective Clearances / app||Aerial Duels Won / app||Goals||Apps||Mins|
As Opta data from last season's Premier League shows, it is a close contest between Caulker and the likes of Martin Sktel, Mamadou Sakho and co. In some areas, the Cardiff man excels. In others, he falls rather short.
In terms of tackles won per game, for instance, no Liverpool defender has a worse rate than Caulker, with Kolo Toure making almost double the amount per appearance. Interception-wise, though, the ex-Tottenham player fares better, though Skrtel and Sakho still outshine him.
It is the next two key areas in which Caulker comes into his own, however, averaging more effective clearances per match than anyone bar Skrtel, while he also averaged more aerial duels won than any other Reds centre-back.
Overall, then, the 22-year-old could easily slot in as third-choice behind Sakho and Skrtel - and no one could deny that Caulker would add something at Anfield.
The fact that the Cardiff man also played every single league game last term suggests his fitness is up to a high standard, while his five-goal tally was only beaten by Skrtel. His youth and relatively cheap price are also big advantages and it would simply be a matter of Rodgers fitting Caulker in, possibly selling an existing centre-back or two.