Real Madrid full-back Dani Carvajal was one of three players to withdraw from Spain's Euro 2016 qualifiers later this week due to an ankle injury.
Real Sociedad centre-back Inigo Martinez and Villarreal midfielder Bruno Soriano have also had to pull out, said the Spanish camp.
"He has been diagnosed with an injury to the peroneal tendons in his right ankle," Real said of Carvajal's injury.
Carvajal, 23, was forced off during Real's 1-1 draw at city rivals Atletico Madrid on Sunday and Spanish media reports claim he will be out for two to three weeks.
Martinez, 24, has a muscular injury while Soriano, 31, is suffering from "post-traumatic arthritis" in his knee, according to the Spain management.
Group C leaders Spain host Luxembourg on Friday before travelling to Ukraine next Monday -- a win in the first or draw in the second will be enough to secure their passage to next year's Euro 2016 finals in France.
Viallarreal's Mario Gaspar was called up to replace Carvajal, while Athletic Bilbao's Xabier Etxeita and Mikel San Jose come in for Martinez and Soriano respectively.
San Jose, 26, has three Spain caps but Gaspar, 24, and Etxeita, 27, will be hoping to make their international debuts.
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