The Chelsea midfielder will return to London on Tuesday afternoon after undergoing tests in Madrid
Fabregas played the whole of Chelsea's 2-1 Premier League win over Liverpool at Anfield on Saturday and was included in Spain's squad for this weekend's Euro 2016 qualifier against Belarus and the friendly against Germany next week
However, Chelsea manager Jose Mourinho said he had taken a "gamble" with Fabregas' fitness by playing him, and the tests in Spain have revealed the full extent of the injury
A statement from the Spanish Football Federation (RFEF) said: "The Chelsea midfielder has been ruled out for the games against Belarus and Germany following tests and an evaluation of his condition that was carried out this morning by the medical staff of the Spanish national team
"The MRI done this morning in the Sanitas Clinic in La Moraleja (Madrid) showed a clear improvement with respect to the one done by his club on Sunday.
"Although the MRI discards a hamstring tear, the player continues to have discomfort and the medical team considers that his involvement in the next games would not be advisable for his complete recovery."
The news will no doubt please Mourinho, who had asked for the 27-year-old to remain in London this weekend in order to recover.
Spain coach Vicente del Bosque has called up Villarreal midfielder Bruno Soriano as Fabregas' replacement.
Fabregas has joined Manchester City's David Silva and Barcelona's Andres Iniesta on the sidelines.
Del Bosque left out Chelsea striker Diego Costa for the upcoming games, with the former Atletico star needing to rest after recent injury troubles of his own.
Spain host Belarus on Saturday before facing world champions Germany in Vigo on November 18.
Source : PA