Ulster full-back Matt Faddes has been ruled out for the rest of the season.
He requires surgery after sustaining a shoulder injury at the weekend.
Faddes started and scored Ulster's second try in Saturday's 26-24 loss to Ospreys at Liberty Stadium in the Guinness Pro 14.
Prop Kyle McCall remains unavailable ahead of the visit of the Cheetahs to Kingspan Stadium after suffering a foot injury in training last week.
In better news for Dan McFarland, centre James Hume has returned to full training having been sidelined since November with a torn hamstring.