"He had a fantastic game against the Blues but he's been a mixed bag since then.
"We had two or three opportunities to score against the Force but poor decision-making cost us."
Into the No 15 jersey comes Hawkes Bay's Andrew Horrell.
A first five-eighths by trade, Rennie said he played plenty of his age-group rugby at Canterbury in the backfield, lacked the explosive pace of Robinson, but had a good rugby brain and timed his runs well.
His selection serves two purposes. Horrell, 23, is pegged as a back-up five-eighths but the good form and rude health of Aaron Cruden and Sonny Bill Williams has meant he's not been required.
This gives him a run as well as giving the talented Robinson a public kick up the proverbial.
"We're trying to put a lot of pressure on Robbie to be even better, to tidy up those mistakes," Rennie said.
The New Zealand Conference have also selected Alex Bradley to make his debut, starting the match at No 8. An injury to Kane Thompson has precipitated that move.
Hika Elliot and Mahonri Schwalger have made their now traditional switch between the starting and bench roles at hooker, while Asaeli Tikoirotuma comes back on to the bench.
Prop Toby Smith, injured in their first-round loss against the Highlanders, was close to selection and should be available to meet the Sharks in Durban next week.
This clash on the high veld pits two of the most attractive sides in the competition on a collision course. The Chiefs know the Cheetahs will want to play a "ruck and run" game from the outset and hope to counter that by controlling possession and the pace of the game.
"If we play without the ball for a long chunk we'll be struggling," said Rennie.
The first 20 minutes might not be pretty from the Chiefs, but they hope it will establish a platform from which they can unleash their backline stars.
"The Cheetahs play the quickest brand of football so it's going to have its challenges. They play a rucking, running style of game and can be lethal from anywhere on the park so we're going to have to be combative with good set-piece," said assistant coach Wayne Smith.
The last time these teams met was in 2010. In the midst of a horror run, the Chiefs managed only a 25-25 draw at Hamilton. The Cheetahs haven't beaten the Chiefs in five attempts, though they have drawn twice.
On a rare two-match winning streak - having beaten the Hurricanes and Lions - the Cheetahs might fancy their chances of breaking that duck.
They'll have to do so, however, against a team that has won five in a row and have learned the art of winning when they're not playing particularly well.
Cheetahs v Chiefs
Bloemfontein, 3.05am tomorrow
Hennie Daniller
Ryno Benjamin
Robert Ebersohn
Andries Strauss
Willie le Roux
Sias Ebersohn
Piet van Zyl
Philip van der Walt
Justin Downey
Heinrich Brussow
I. Westhuizen
George Earle
W.P. Nel
Adriaan Strauss (c)
Coenie Oosthuizen
Hercu Liebenberg, Trevor Nyakane, Andries Ferreira, Ashley Johnson, Tewis de Bruyn, Johan Goosen, Philip Snyman.
Andrew Horrell
Lelia Masaga
Richard Kahui
Sonny Bill Williams
Tim Nanai-Williams
Aaron Cruden
T. Kerr-Barlow
Alex Bradley
Tanerau Latimer
Liam Messam
Brodie Retallick
Craig Clarke (c)
Ben Tameifuna
Hika Elliot
Sona Taumalolo
Mahonri Schwalger, Josh Hohneck, Michael Fitzgerald, Sam Cane, Augustine Pulu, Asaeli Tikoirotuma, Robbie Robinson.
