Quinn Roux comes in for Connacht in the only change for their opening European Champions Cup game against Toulouse.
Ireland's only remaining European survivors Connacht face Grenoble in the Challenge Cup quarter-finals on Saturday.
South Africa-born Quinn Roux is handed his debut as Ireland make five changes for the second Test against the Springboks.
Team news as Saracens host Toulouse in Saturday's European Rugby Champions Cup fixture at Allianz Park (17:30 GMT).
Exeter must beat Ulster to have a chance of making the knockout stages of Champions Cup, says boss Rob Baxter.