Iran coach Branko Ivankovic faces a worry ahead of Saturday's game against Portugal, with the news that his captain Ali Daei has a back injury.
Veteran Daei felt discomfort in his back after Sunday's defeat
The striker sustained the problem in Sunday's Group D opener against Mexico, which his side lost 3-1.
And Ivankovic is not optimistic the 37-year-old will recover in time for the crucial match in Frankfurt.
"Ali did not train on Monday because of a back injury. It will be very hard for him to face Portugal," said Ivankovic.
Daei's injury is the latest of a troubled World Cup campaign for the Iranians so far.
Key midfielder Mehdi Mahdavikia played through the pain of a thigh problem against Mexico, while keeper Ebrahim Mirzapour almost had to sit out the match because of jet lag.