Salah continued his remarkable start to life at Anfield last month, netting five goals and laying on a further three as the Reds remained unbeaten across seven fixtures.
Firmino, meanwhile, scored six and set up two, playing a key role in the four wins and three draws the Reds accrued.
Those efforts have seen the pair nominated for recognition from the Premier League, with Salah aiming for a second consecutive POTM award.
Back either Salah or Firmino to win the accolade by casting your vote at premierleague.com/stats/awards before midnight on Monday January 8.