The Bulls will know by Wednesday if Jurgen Visser, Flip van der Merwe and Akona Ndungane will be fit to face the Waratahs in Sydney on Saturday.
Visser (foot), Van der Merwe (bicep) and Ndungane (hamstring) will undergo final fitness assessments on Wednesday before team selection, team doctor Org Strauss confirmed.
Strauss also revealed that Dewald Potgieter had successful surgery on his torn bicep. The player will be out of action for six months.
Deon Stegmann, who also returned home from the team's tour of Australasia due to a groin injury, will undergo surgery on April 23. This could rule him out for at least four months.
Pierre Spies (bicep), Arno Botha (knee) and Frik Kirsten (neck) remained on the long-term recovery list.