The Scotland midfielder missed the defeat at home to Wigan along with forward Craig Bellamy (calf), midfielder Maxi Rodriguez (illness) and defenders Glen Johnson (calf), Daniel Agger (rib) and Martin Kelly (ankle).
While some of those are edging closer to a return Adam will have to wait for another assessment.
Kenny Dalglish: "Charlie's another two weeks and then we'll find out a proper diagnosis without people speculating what's wrong.
"Rather than be inaccurate or incorrect or someone making up a story we will wait and see in a couple of weeks how long he's going to be out."