Taarabt was on international duty with Morocco and Helguson was away with Iceland, as Rangers beat Exeter 5-0 in the Carling Cup on Tuesday night.
Argentinian midfielder Alejandro Faurlin, Rangers' £3.5million summer recruit, is back in full training following a thigh injury but is likely to wait until Tuesday's trip to Bristol City for his debut.
Rookie striker Angelo Balanta is fit after a knock sidelined him in midweek and Akos Buzsaky has fully recovered from a thigh problem, so midfielders Lee Cook and Martin Rowlands are the only definite absentees.
Cook is still recovering from a summer clean-up operation on his knee and Rowlands suffered an ankle injury during the opening-day draw with Blackpool and will be out for a couple more weeks.
