Spain will be without injured trio Dani Carvajal, Alvaro Morata and Andres Iniesta for their upcoming World Cup qualifiers against Albania and Israel.
Julen Lopetegui will name his replacements on Monday, ahead of Friday's hosting of Albania and Spain's trip to Israel in Group G on October 9.
Real Madrid full-back Carvajal is set for an indefinite spell on the sidelines after being diagnosed with a viral infection that is affecting his pericardium, the membrane enclosing the heart.
The 25-year-old featured in Tuesday's Champions League win at Borussia Dortmund, having started Madrid's first six LaLiga matches this season.
A left hamstring injury sustained during Chelsea's 1-0 loss to Premier League leaders Manchester City on Saturday ruled Morata out of the pair of international fixtures.
Morata had scored seven goals in eight matches since arriving from Spanish and European champions Madrid before hobbling off in the 35th minute at Stamford Bridge.
Barcelona captain Iniesta is expected to be sidelined for 10 days after suffering a left hamstring problem during Sunday's 3-0 victory over Las Palmas, which was played behind closed doors.
Spain are three points clear of Italy atop Group G with two matches remaining.