Ablett will play for the first time against his former club since switching to the Suns in the pre-season.
Last week on Fox Sports' On The Couch, former Geelong teammate Paul Chapman didn't rule out sledging Ablett and said the Cats would have to play team defence to stop him.
"We know Gary and what works for him and against him and sledging might work, it might not," Chapman said.
"We know him quite deeply obviously but when we go out against him he's an opponent like any other great player. He's fit, he's strong, he's hard to stop."
McKenna said he expected the Cats to be physical not just against Ablett, but also against the rest of his young team.
"[The] Geelong boys are a hardened professional side, I'm sure there'll be a few blokes there wanting to put a notch on their belts and put Gary on his backside and Gary I'm sure will be keen to do likewise," McKenna said.
"As a team I think we've got to look out for him and help him through the game.
"I'm sure as far as motivation goes Gary is a professional and motivated 10 out of 10 for each week but there'll certainly be a bit more because it's his old side."
McKenna said the 8-0 had been the benchmark so far this season, and while full of praise for them, was eager to test the development of his team.
"No matter where you play good sides they're always going to be tough. Geelong are undefeated, [we're] coming off the bye, all those things conspire against us but that's going to be a challenge for the old players, the young players, the club itself and our fans as well.
"To test yourself against the best is ultimately what we need to be able to do."
