"It is not ideal but if he comes through that session later in the week and does a captain's run then he will play," Rennie said.
He was a calming influence on the side, very experienced and one of their key men in the tactical lineout battle.
There were options if the Chiefs skipper was sidelined - Mike Fitzgerald or Romana Graham were locks in the squad or Kane Thompson could shift into lock from No 8.
Meanwhile the travel-weary Sharks are holding their squad in Sydney where they will train before flying on Friday to Auckland and moving to Hamilton for the competition conclusion.
While their opponents were travelling, the Chiefs went through some gym work, a theory session, haka practice and then headed for the pool.
"We were going to run them but they were still quite sore after the weekend and if we were going to Africa we would have been travelling anyway and would not have trained so we made the most of it and had a bit of fun," Rennie said.
The serious work would start today towards a final which will be refereed by Steve Walsh with touchline assistance from Craig Joubert and Keith Brown, with Garratt Williamson the television match official.
The Super 15 final will be the last franchise game for Sonny Bill Williams before he moves offshore after a season where he has played in every game and missed just one quarter, against the Lions.
Only his five-eighths partner Aaron Cruden has played more minutes, missing just seven against the Cheetahs because the staff wanted to test Andrew Horrell in that role.
"We've got 16 round-robin games plus two finals games out of Sonny, so we've got our pound of flesh," Rennie chortled.
"Both those boys have had a very big workload. They have both been huge for us and Sonny has been magnificent getting us gainline and giving us quick ball and the ability to create space around him as well.
"He has said all along he wants to win a championship with these boys so we've got 80 minutes to get that right I guess."
Rennie said the franchise had not settled on a replacement but they had their eye on former captain and 100-test All Black Mils Muliaina.