So a few possible examples, not intended to upset anyone over their favourites, but potential perspectives.
MASCHERANO - still young, but has he improved in areas such as passing, shooting etc as he could have
BABEL - young, not getting many starting opportunities, but seemed to be a lot better as sub last season than this.
SKRTEL - hitting the kind of age where he should be settling in at CB and putting in solid performances, but has he disappointed this season?
ARBELOA - been a bit disappointing this season, to such an extent I think a lot of LFC fans are looking at a new RB and who would have thought that last season?
CARRAGHER - is he 0.0135 m/s slower than three seasons ago?


I guess you could do this thus :
MASCHERANO*
08/09 : disappointing, room for improvement
good enough : tackling, mobility.............
not good enough : passing, shooting...........
*not picking on Mascherano, just perhaps easier to work with given his role