Thilthorpe was a late withdrawal from Friday night's 25-point win over West Coast after falling sick on the morning of the match.
"We're not sure whether Riley's eaten something or whether it's a virus, but he went down pretty quickly this morning," Adelaide coach Matthew Nicks said after the 15.9 (99) to 11.8 (74) win.
"I don't actually know how he's doing at the moment.
"I'm pretty sure he's out cold trying to sleep it off, but hopefully this is something sharp and quick that rips through him, and then he's OK to go next week."
Thilthorpe will be further assessed before a decision is made on whether he can fly back with his teammates to Adelaide on Saturday.
"We wouldn't put Riley on a plane straight away," Nicks said, joking he would tell Thilthorpe to "not touch anyone".
"I don't actually know whether it's just a quick virus, whether it's food poisoning. We're not sure, so it's not something I can't answer.
"But we won't put anyone else in harm's way, or any of the players. Maybe he stays for 24 hours, I don't know."
The Crows improved their record to 10-6 with the win over West Coast, and they had Darcy Fogarty's four first-half goals and a heroic performance from captain Jordan Dawson to thank.
Dawson finished with 27-disposals, six clearances, 764m gained and one goal in a best-on-ground performance.
The 29-year-old also took two crucial marks deep in defence early in the final quarter after West Coast had closed to within 18 points.
"His football IQ is at another level," Nicks said.
"He knows where the team needs him at different times. He's got a certain license to play and feel the game out.
"When he started to feel momentum, he was able to make a real leader's decision and put himself where we needed him."
Nicks was pleased with how his team bounced back from last week's shock 26-point loss to Port Adelaide, when the Crows lost the clearance battle 42-22.
Against the Eagles, Adelaide won the centre clearances 7-1 in the opening term in what proved a crucial platform for them kicking eight of the first nine goals of the match.
The Crows will be aiming to make it two wins on the trot when they host Gold Coast next week.
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