Real Madrid's Toni Kroos is the latest Germany star ruled out of Friday's 2018 World Cup qualifier away to San Marino with a fractured foot.

The 26-year-old misses the qualifier, four days before Germany's friendly against Italy in Milan, with a hairline fracture of the metatarsal bone.

Spanish sports daily Marca say the German international may need surgery and claims Kroos could be ruled out for up to three months.

He suffered the injury in Sunday's 3-0 Spanish league win over Leganes and can not train for the next ten days, the German Football Association (DFB) announced Tuesday.

Kroos had the injury confirmed after a scan in Munich with the national team doctor Hans-Wilhelm Mueller-Wohlfahrt.

The attacking midfielder joins centre-back Jerome Boateng, who was forced out of Germany's qualifier after injuring the groin and knee on his right leg in Bayern Munich's 1-1 draw with Hoffenheim on Saturday.