"For me it is very different. We need to make sure we have a huge game so guys need to bring fresh legs and fresh enthusiasm," Kirwan said.
"Some of our guys have got high k's and it's important we give them a bit of a break," he said.
The visitors, who have won just two games this season, have been hit by further problems with troubled Wallaby Kurtley Beale stood down again after breaking a drinking ban imposed on him.
Beale missed a month's play after hitting several teammates during a bout of drinking in South Africa. He returned from the bench with a strong display last week against the Chiefs and then went out drinking with teammates.
His immediate future and chances of playing against the touring British and Irish Lions next month will form part of an Australian Rugby Union investigation. Kirwan could not conceal his smile about Beale's ban while he warned about the strong challenge from the Rebels, who now would have one fewer x-factor players.
Former skipper Keven Mealamu and midfield back Jackson Willison had slight injuries and needed time out while Luke Braid had a huge workload at openside and deserved a spell.
Steven Luatua has recovered from the ankle strain he suffered against the Stormers while Ranger would return to his preferred position at centre.
If the Rebels thought the Blues would underestimate them, Kirwan said they would be well off the mark.