Chelsea continue sweating over the fitness of Diego Costa after the Spanish national team confirmed that the striker missed a second training session of Julen Lopetegui's squad on Wednesday (9 November). The news comes only a day after reports in Spain revealed that the former Atletico Madrid star had joined his national team with some groin pain.

Spain, who are level on seven points at the top of their World Cup qualification group with Italy, face a qualifier against Macedonia on Saturday (12 November) three days before a friendly with England at Wembley.

Costa failed to make the Spanish squad for Euro 2016 under Vicente Del Bosque but has regained a predominant role with La Roja since the arrival of Lopetegui. He was expected to lead Lopetegui's attack ahead of Real Madrid's Alvaro Morata against Macedonia following his impressive start to the season at Chelsea, having scored nine goals in 11 games to become top scorer in the competition.

But on Tuesday it emerged that Costa had some niggles in his groin and a medical report from Chelsea warning his country about his tiredness – despite him playing the full 90 minutes during the weekend victory over Everton.

Yet, Marca and AS reported that Spanish national team doctors played down fears over a major injury after a medical test only found a groin bruise. Those initial reports claimed that Spanish doctors will be monitoring his condition in the hope he will be ready to play against Macedonia.

However, his availability is now in doubt after he couldn't train with the rest of his teammates on Tuesday and Wednesday. Spain confirmed his absence from the sessions through the official website, adding that the Chelsea star worked instead on his own, but did not give an update on his problems.

"Diego Costa has been the only player who has not gone to the pitch," Spain confirmed. "The Spanish-Brazilian has worked alone in another field of the Spanish training ground."

Antonio Conte will be monitoring the situation as the striker has become a key player since his arrival at Stamford Bridge. Yet, his absences from the past two Spanish training session shouldn't be a major concern for Chelsea as the Blues don't have another Premier League game until 20 November, when they will visit Middlesbrough.