The former Real Madrid winger was forced withdraw from the Oranje starting line-up for the 4-1 win over Hungary on Tuesday due to the injury.
He has since returned to Germany, but sat out training on Thursday and it is not yet clear if he will practise with the squad on Friday, throwing his participation in Saturday's match with Mainz into doubt.
Should the Dutchman fail to recover in time for the clash, Swiss youngster Xherdan Shaqiri will take his place in attacking midfield.
After failing to win a single trophy last season, Jupp Heynckes' side will be hoping to continue their current run of form as they look to claim their third win in as many Bundesliga games.
They meet Mainz at 15:30CET at the Allianz Arena.