Other players are beaten up. Liam Messam, who celebrated his 100th game for the Chiefs in the 35-24 victory at Port Elizabeth, injured an ankle in a tackle late in the match, and the joint was badly swollen after the match.
"Hopefully it won't amount to much," Rennie said.
On the positive side, lock Brodie Retallick's hip injury stood up well - he entered the match from the reserves bench after not being able to train all week - and Sam Cane suffered no ill effects from the stitches in an ear put in after the Stormers match in Cape Town.
Rennie is expecting "desperate" Highlanders at Waikato Stadium, as Joseph's men continue their search for a first win of the season.
However, their style shouldn't come as a surprise.
"We've played them twice already this year, unbelievably," said Rennie. The Chiefs beat the Highlanders in a pre-season match in Taupo and accounted for them 41-27 in their first competition game of the season in Dunedin.
"We'll have to be a hell of a lot better than we were [against the Kings]," he said.
One area of concern will be the breakdown, where the Chiefs were again heavily penalised and lost replacement halfback Augustine Pulu to the sinbin in the second half.
The week prior they lost both Tawera Kerr-Barlow and Nick Crosswell to the bin.
"It's a major concern," Rennie said. "We seem to be counter-rucking okay, but as soon as we put our hands in we are getting penalised.
"Smithy [assistant coach Wayne Smith] has done a lot of work in that area and it's disappointing."
The Kings - who lost lock and captain Darron Nell before kick-off to a calf injury - scrapped and scrambled, but looked vulnerable when the Chiefs spread the ball.
Lelia Masaga, sporting a cut on his left cheek, cashed in with three tries; flanker Sam Cane, who replaced Filipo, scored the other in the second half when bulldozing over from close range.
The Kings' 18-year-old speedster, Sergeal Pietersen, scored a popular 90m try just before halftime when capitalising on a misunderstanding between Aaron Cruden and Masaga, and No 8 Jacques Englebrecht dived over from close range after Pulu's departure.
The new kids on the block came closer to the Chiefs than expected, which annoyed Rennie.
Although he was disappointed with aspects of their win and narrow loss in Cape Town - where they got two bonus points - seven points from two games was a good haul in the Republic.