It's a headache for Rennie that may persist beyond the weekend, with Tamanivalu only a chance to be fit for any potential semifinal, and one that would have further soured the coach's mood after home advantage slipped through his side's fingers.
Even a draw against the Highlanders would have set up a quarter-final in Hamilton but the Chiefs were bested by the defending champions for a sixth straight time, sending them on an early-morning flight to Cape Town tomorrow.
There, they will encounter the unknown, given the Stormers have yet to face Kiwi opposition this season. The players are set for a stint of video analysis on the flight to the Republic and, when they complete their scouting, the Chiefs are unlikely to be too worried about what they see.
The Stormers have beaten only one other playoff side this season - a home victory over the Brumbies - while in May they were held to a draw against the last-placed Sunwolves. But, having headed into the playoffs with three defeats in their last six matches, Rennie was more focused on his own side.
"I haven't seen much of [the Stormers] at all, to be honest," he said. "I've done a bit of homework on other teams but we've got a bit of catching up to do. I've seen them play a few games but there will be a fair bit of focus on us - tidying up parts of our game."