Spain's Diego Costa misses Macedonia clash and is replaced by Iago Aspas

Diego Costa will miss Spain's World Cup qualifier against Macedonia on Saturday with a muscular problem, the Spanish football association has confirmed.

The news was confirmed soon after coach Julen Lopetegui said he hoped the Chelsea striker still had a chance of playing in the match.

In a tweet, Spain said Costa would be replaced in the squad by Celta Vigo's Iago Aspas.

Spain coach Julen Lopetegui also won't be able to count on playmaker Andres Iniesta, striker Diego Costa, defender Gerard Pique, left back Jordi Alba and defensive midfielder Javi Martinez.

"We are going to try to turn difficulties into opportunities," Lopetegui said. "We can't lament anything. I'm happy with the players that we called up, and they are going to help us achieve victory in both matches."

Costa, 28, scored one goal and set up another in Chelsea's 5-0 triumph over Everton on Saturday but has missed Spain's two opening training sessions in Madrid with muscle fatigue and a left groin bruise.

In a short statement, Chelsea said: "Diego Costa has been replaced in the Spain squad for their matches against Macedonia and England having been unable to take full part in training due to injury."

Earlier, Lopetegui had told Onda Cero: "We will see how he progresses. It's true that his recovery has not been as positive as we had expected.

"But we are hopeful that he will feel better tomorrow and we can take a small step forward thinking ahead of Saturday's game. We have to wait."

Brazil-born Costa had a slow start to his Spain career but has been in good form for Chelsea this season, scoring nine goals and setting up three more in 11 Premier League starts.

He has played in all four Spain games since Lopetegui replaced Vicente del Bosque at the helm of the national team in July and started three, scoring three goals.

With Costa not playing up front, Alvaro Morata and Aritz Aduriz should get a chance to perform alongside each other in the lineup. Other forwards in the squad include Lucas Vazquez, Nolito, Jose Callejon and Vitolo.

"It's great to have so many options," said Aduriz, who was called up after scoring five goals in an Athletic Bilbao win in the Europa League last week. "We are all here to help."

Lopetegui will have to work extra hard to set up his defence, which is not used to being without veteran central defenders Ramos and Pique at the same time. Ramos is nursing a left knee injury, while Pique is recovering from sprained ligaments in his right ankle.

"We've had to restructure the defense the best way possible," Lopetegui said, not dismissing the possibility of having to improvise with right back Cesar Azpilicueta at centre-back.

At midfield, it will be difficult to substitute for Iniesta, who has been sidelined because of right knee injury. Among the options available for Lopetegui are Juan Mata, Thiago Alcantara and Koke.

"Some important players couldn't come because of injuries, but that creates an opportunity to those who are here,'' goalkeeper Sergio Asenjo said.