Etzebeth was ruled out for four weeks after being send for scans following a chest injury sustained last Friday evening in the warm-up game against the Cheetahs at Newlands, won 39-31 by the Stormers.
Etzebeth left the field shortly before halftime, while Carizza was ruled out for three weeks following a shoulder injury which forced him to leave the field after just 15 minutes.
At least no fractures were reported and it was especially uplifting news for Etzebeth who missed the Stormers entire campaign due to torn ankle ligaments last year and also the June Test matches of the Boks.
The Stormers reported more positive news on their two wings EW Viljoen and Kobus van Wyk who were also injured during the same game.
Van Wyk will need a rest period of 10 days following a calf injury, but could meet the deadline for the Loftus derby, while Viljoen was cleared of concussion after he passed the test but needs a rest period of seven days.
A big hype is building for the Loftus clash after the Bulls won both their warm-ups 30-13 against the Cheetahs and 39-26 last weekend against the highly rated Saracens in London.
The Stormers are also looking to be in fine form following their 34-3 win over the Eagles and the 39-31 result over the Cheetahs.
Since the conference system was introduced the Stormers won the SA version in 2011 and 2012, the Bulls in 2013 and the Sharks last season.
A flyhalf crisis, followed by a spate of injuries to their looseforwards and a lock crisis last year deprived the Stormers of any continuity, but they appear to have to rekindled their spark of three years ago.
And to a huge extend their scrum seems to be the firing again with the return of strongman Steven Kitshoff and the arrival of Puma strongman Vincent Koch.