Monk has been out of action since limping off with a knee injury in the 4-0 FA Cup third round win over Colchester United on 8 January.
Spaniard Orlandi pulled up with a thigh strain in the 2-1 defeat to Leyton Orient in the fourth round.
It will be the second return to action for Orlandi who had only just made his comeback from a month on the sidelines after injuring his other thigh on New Year's Day.
The return of Monk will leave boss Brendan Rodgers with a full complement of defenders after full-backs Neil Taylor and Angel Rangel recently returned to full fitness.
It had first been feared Monk would be out for three months after suffering ruptured knee medial ligaments in their FA Cup victory.
But that recovery time was reduced to between six and eight weeks after receiving a specialist medical opinion.
Meanwhile striker Gorka Pintado has been ruled out for up to nine months after suffering a cruciate knee ligament injury while playing on loan for Cypriot side AEK Larnaca.
Source: BBC Sport
Source: BBC Sport