The 24-year-old was previously on loan at Southampton and failed to make an impact.
Against West Ham, however, Caulker was largely solid for Liverpool. And Marsh went as far as to laud the centre-back for his cup display.
Responses from fans were mixed, with some criticising him and some West Ham supporters suggesting he should have been penalised for a handball in the box.
But it seems Liverpool supporters generally agreed with Marsh about the on-loan QPR defender.
Any one notice how excellent Caulker was today ?— Rodney Marsh (@RodneyMarsh10) January 30, 2016
So the big question: if Caulker can produce while at a club like Liverpool, why didn't he bother at QPR?
The 24-year-old struggled at Southampton but was even worse during his time at the R's. Is there hope for his career at Loftus Road or is he destined to stay at Anfield... Or neither?