Dermot Corrigan of ESPN FC also provided context on the report:
The 36-year-old has a contract in Portugal that runs until the summer of 2018, but his signature may be a cost-effective one in the event the Reds decide to push ahead with their pursuit of a transfer.
Liverpool manager Jurgen Klopp signed Loris Karius last summer as competition to incumbent Simon Mignolet, who has now wrestled his No. 1 spot back from the German.
However, one might argue that both stoppers are somewhat lacking in experience, and the same can't be said for Casillas, a veteran of the European circuit on a level that few others can match:
While Liverpool's attack was, at times, one of the most threatening in the Premier League this past season, the same can't be said of the club's back line, which conceded 42 goals, the third-most of any team in the top seven.
Casillas could be a difficult target to lure, however, when one considers the Spaniard has previously suggested he's content in the Primeira Liga, per Metro's Portuguese football expert Jan Hagen:
The veteran has proved he's still got the ability to compete at the top level and played his part in a Porto team that leaked only 19 goals in 34 league games this season, although he conceded just 16 of those.
Those figures suggest Casillas has lost very little of his potency as he's aged, although it's unclear whether Klopp has stolen the edge in his bid to land the three-time UEFA Champions League winner.