Bulls coach Frans Ludeke will be sweating over the fitness of injured captain Flip van der Merwe, ahead of the next phase in their Super Rugby campaign.
The embattle Bulls enter the second half of their Australasian tour when they face the Waratahs in Sydney on Saturday.
And they have paid a heavy price in the first two matches on their tour - a 20-25 loss to the Hurricanes and a 20-27 loss to the Highlanders.
Van der Merwe, Jurgen Visser and Akona Ndungane joined Dewald Potgieter and Deon Stegmann as injury casualties on tour.
Potgieter and Stegmann were both injured against the Hurricanes.
The Bulls coach, Ludeke, will only know on Wednesday if Visser, Van der Merwe and Ndungane will be available for selection this week.
Visser (foot), Van der Merwe (bicep) and Ndungane (hamstring) will undergo a final fitness assessment on Wednesday before team selection, team doctor Org Strauss confirmed.
Strauss also confirmed that Dewald Potgieter had successful surgery on his torn bicep.
The player will be out of action for six months.
Stegmann, who also returned home due to a groin injury, will undergo surgery on 23 April.
This could rule him out for at least four months.
Pierre Spies (bicep), Arno Botha (knee) and Frik Kirsten (neck) remains on the long-term recovery list.