Transfer stories very rarely have a direct quote until it's a done deal though. If there is a quote in a story such as this, where it's being reported the team won't try to strengthen a particular position, it's often a lie anyway.
In my experience, Sky Sports are usually pretty reliable themselves, although they do cite other media outlets indiscriminately.
I'm not mad about this news, which is a surprise given what I thought of Mignolet as recently as a few months ago. He's been much, much better since coming back into the team this season and, while Karius is clearly Klopp's man long term, I think the #1 spot is Mignolet's to lose.