Stormers coach Allister Coetzee said players needed a complete break when the flu bug struck. He also sent home Bryan Habana for the same reason.
"As soon as we know a player is infected we send him home because he needs to be isolated," said Coetzee.
"This flu is contagious and we'll see how De Jongh feels on Tuesday. Centre Marcel Brache, who played as a first-half replacement on Saturday, has also been bitten by the bug."
The only good news was that first-choice lock Rynhardt Elstadt has served his suspension and will be available for Saturday's fixture against the Cheetahs in Bloemfontein.
With three No 8s out on the side lines, Coetzee used openside flank Siya Kolisi in the No 8 berth over the weekend. He proved to be a tremendous success.
However, Coetzee may have a change of heart after he said on Monday: "You can see Siya is a natural No 6."
Coetzee said Mondays at the training camp were terrible because most players suffered bumps and bruises in the weekend's matches.
Another big setback for the Stormers is that Springbok lock Eben Etzebeth, one of the finds of the season, will be a spectator this week, but he will be ready to play against the Rebels, in the Stormers final league game.
Coetzee is hopeful the side returns to the powerful scrums which they produced earlier this year. The return of Steven Kitshoff will help to steady the Stormers scrum.