According to The Guardian's Louise Taylor, Brendan Rodgers acknowledged prior to the Norwich match that getting his defensive partnership right was now a priority.
That Rodgers opted for Daniel Agger alongside Martin Skrtel for the visit of Norwich, then, may signal that they are his preferred choice at the heart of the Reds defence.
Skrtel has become a first choice under Rodgers this season despite looking to be heading out the door in the summer, while Agger has been dropped/rotated for Mamadou Sakho and Kolo Toure.
Sakho has been cast aside since the 2-0 defeat to Arsenal—an unused substitute for every match since.
It's likely that Rodgers will stick with the same back four that started against Norwich, although you wouldn't bet against changes yet again given the rotation so far this season.
Jon Flanagan should keep his place at left-back, while the lack of competition at right-back means Glen Johnson will keep his despite two less-than-impressive performances this week.