Worryingly for South African head coach Peter de Villiers, it is the same hand du Preez broke during last year's Super 14 clash with the same opposition.
Du Preez was in stunning form during the Boks' 2007 World Cup triumph and the 26-year-old is expected to play a key role in their summer series against the Lions in June and July of this year.
A fractured hand would seriously eat into du Preez's preparation time for the Lions tour but, according to his club doctor, the injury is not anticipated to be too serious.
"We will know everything on Fourie today depending on his condition," said Dr Org Strauss.
"It doesn't look like a fracture and I don't think it is.
"There is some inflammation on the thumb where he broke his hand last year, but it is hopefully not too serious."