Elton Jantjies has been ruled out for three to four weeks after fracturing a finger against the Jaguares on Saturday.
The flyhalf will undergo an operation on Tuesday that will rule him out of the Lions' next two matches against the Bulls and Sharks.
He is also likely to miss the first two Tests of the series against Ireland, with Pat Lambie now expected to wear the No 10 jersey.
In another bit of bad news for the Lions, back-up flyhalf Jaco van der Walt sustained a knee injury and will be out for six weeks, while Corné Fourie injured his ribs and will need to pass a fitness test this week in order to be cleared to face the Bulls on Saturday.
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