Riewoldt had been pushing to come back from a knee tendon injury but his bid was given the thumbs down by club doctors.
Saints coach Scott Watters said he was unsure when Riewoldt would rejoin the side, refusing to confirm whether the star forward would sit out for more than one match or not.
However, Watters said scans showed Riewoldt's injury, caused in the round-20 game against Melbourne, was not serious.
The spearhead underwent scans shortly after hurting his knee and on Tuesday had further tests which again showed damage to a tendon behind the knee.
"He's not quite right," Watters said. "It is minor but it is still probably having an impact on his function right at the moment despite the improvement."
Watters said Riewoldt had made a determined bid to prove his fitness but could not sway doctors.
"Nick's pretty brave at the best of times and he wanted to push the envelope as much as possible," Watters said.
"There was significant improvement from Monday to today but, functionally, it's one thing to put up with pain, but if there's still a functional limitation, you can't go past that.
"He gave it his best shot but we now move on and focus on the players which will actually have an impact."
Watters said it was pointless keeping Geelong guessing by leaving a decision on Riewoldt until the last minute.
"I'm not into playing games," Watters said. "I've got a lot of faith in the players we'll select.
"Sometimes, those games are overrated and you actually distract your team from where they're at.
"Another 48 hours won't make any difference."
Watters said that while Riewoldt was an important player, his attention was centred on the team.
"It's never really been about the individual for us, from a forward line point of view," Watters said.
"We've had weeks where different forwards have had a really big impact - it's always been about the six or seven who go through those roles.
"That probably puts us in a pretty good space when this sort of thing occurs.
"While Nick's a really important part of all of that, he's not the only part."