Rioli tweaked the injury late in the final quarter of last week's clash with North Melbourne and while he could have played this week, the Hawks decided to keep him fresh for next weekend's opening final.
"There's just no point," said Hawks coach Alastair Clarkson before the Hawks boarded the plane to Sydney.
"We've been really cautious with our players this year making sure they're fit and energised for our finals campaign so we won't take any risks."
The coach said the Hawks wanted to minimise the risk of Rioli getting another knock or someone falling across his ankle.
"If we wanted to push the envelope, Cyril would have played. But he's played six games since his hamstring injury so it is probably the perfect time to get his body right and launch into the finals next week."
Midfielder Liam Shiels won't play against the Swans after also hurting his ankle last week.
Clarkson said the Hawks' main aim on Friday night was to play some good football.
He said with a top two berth locked in and two home finals guaranteed, the result against the Swans was almost immaterial.
But the Hawks won't be too vanilla with their approach and have prepared tactically for the match, even though the chances are strong that they'll meet the Swans once again in the opening week of the finals.
"Winning form is good form and we don't want to muck around with that and we'll be going into the game with strategies that will help us defeat the Sydney Swans and I dare say they'll be trying to do the same thing," said Clarkson.
"We don't want to flirt with anything and the result is a little inconsequential, but we still have a bit to play for, which is top spot.
"We still want to prepare ourselves for our finals campaign."
Clarkson has discounted the Swans recent patchy form and their long injury list, saying they will be a "formidable" opponent both on Friday night and in the finals.
Hawk forward Jarryd Roughead leads the Coleman Medal by three goals, which adds another level of intrigue to the match.
Clarkson harked back to the final match of 2008, in which Lance Franklin needed two goals to reach a century, when asked whether the side will especially look out for Roughead.
"It's just an added bonus, really," he said. "If it happens, it happens, but we're not going to compromise how we play the game or the way we prepare for it.
"'Roughy has been a consistent performer for us and if he gets on the end of it tomorrow night, then terrific, but if he doesn't, then he and I aren't too worried about it," he said.
Vice-captain Jordan Lewis and small forward Paul Puopolo, who both missed last week against the Kangaroos, flew with the team to Sydney, with Matt Spangher and Jonathan Simpkin also in the travelling party.
The Hawks will finalise their side after training at ANZ Stadium on Thursday afternoon, where they have only played once before - and lost - in early 2009.
Those who are left out of the side will return home on Friday night so they can play with Box Hill in the VFL finals the following day.
