"Aaron's gone back to Arsenal, he's not available tomorrow," Giggs told reporters. "His injury didn't clear up in time so it's obviously a blow.
"We have plan B and we've worked on it during the week. He was in good form but it gives a chance for someone else."
Wales are already without the injured Ethan Ampadu (back), Sam Vokes (groin) and Tom Lawrence (ankle) for the match in Cardiff.
Ramsey, whose contract with Arsenal expires this year, is set to join Italian side Juventus in the close season after signing a four-year deal with the reigning Serie A champions in February.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
(Reporting by Rohith Nair in Bengaluru; Editing by Toby Davis)
