The Bulls and SA Rugby have reportedly received an official letter demanding an explanation for why the Pretoria outfit fielded a weakened side in their Champions Cup quarter-final.
Northampton advanced to the Champions Cup semi-finals on Saturday, after beating the Bulls 59-22 at Franklin's Gardens.
The Bulls have left many of their star players at home for their Champions Cup quarterfinal clash against Northampton Saints in London on Saturday.
The Bulls will tackle Northampton Saints without many of their Springboks in the Investec Champions Cup quarter-final at Franklin's Gardens on Saturday.
SA Rugby has clarified how the Bulls are travelling to London for their Champions Cup quarterfinal against Northampton Saints on Saturday.
Bulls boss Jake White took aim at SA Rugby following his side's victory over Lyon in the Champions Cup on Saturday.