Shawcross, an ever-present in the Premier League this term, was forced off with a groin injury in the second half of Stoke's League Cup defeat to Manchester United on Wednesday.
With Robert Huth - Shawcross' regular central defensive partner - still absent following knee surgery, manager Mark Hughes will be particularly keen for his skipper to face Villa.
However, it remains to be seen whether the 26-year-old can prove his fitness.
Commenting on the fitness of Huth and Shawcross, Hughes said: "Robert is still unavailable, and Ryan hasn't trained yet. We are going to give him as long as we can.
"He will have a fitness test tomorrow (Saturday) morning. If he isn't available, we will have to rearrange a few things and make a few changes.
"He is a doubt at the moment."
Revealing other injury concerns, the Stoke boss added: "Crouchy (Peter Crouch) is a bit of a doubt too and Jon Walters has a bit of a problem with his ankle.
"They are both doubtful, but the real worry is with Ryan.
"If we have to leave him out (against Villa) to be sure of having him over the Christmas period we will do that, because we certainly don't want to lose him long-term."
Stoke will definitely be without Stephen Ireland on Saturday, with the on-loan midfielder prevented from playing against his parent club.
Hughes is hopeful the midfielder will choose to remain at the Britannia Stadium when his season-long loan, and Villa contract, expires at the end of the season.
"In Stephen's mind he doesn’t see his long-term future at Villa," said the Welshman.
"He will have offers - I am sure of that - but hopefully he sees his future here.
"He has been really good for us, and we will miss him (this weekend). We have other players who play that role, though, so I'm not too worried."
