"The Blues are getting players back and are on the improve," Rennie said.
"Games where the Chiefs play the Blues always have test match intensity and that's what we're preparing for."
Rennie has made several changes to his side for tomorrow night's clash at North Harbour Stadium in Albany. Flanker Sam Cane, fresh off the All Blacks wider training group camp gets a start due to Tanerau Latimer's patellar tendinitis.
Craig Clarke has a minor neck injury and both he and Latimer have not bounced back quickly enough for selection. Clarke is replaced by Michael Fitzgerald.
With four fit, in-form props to choose from, Rennie has selected Chiefs top try scorer Sona Taumalolo and Ben Afeaki along with hooker Mahonri Schwalger for his starting front row. Prop Ben Tameifuna is on the bench.
Maritino Nemani swaps places in the No14 jersey with Lelia Masaga, who moves to the reserves. Lock Romana Graham gets his first call up for the season on the bench.
He is joined by loose forward Scott Waldrom and hooker Hika Elliot.
Kick off tomorrow night is at 7.35pm
Tonight, the Crusaders host the Highlanders, who beat the Blues last week 27-20, kickoff at 7.35pm. The Rebels host the Brumbies in Melbourne with the match set to get underway at 9.40pm.