The Brazilian-born striker could be set to represent La Roja having recently acquired Spanish citizenship.
With La Roja's coach set to announce his squad for October's round of World Cup 2014 qualifiers against Belarus and Georgia on Friday, all eyes are on the in-form striker as he mulls over his international future.
The 24-year-old has hit the back of the net eight times in just seven games this season, including a crucial winner in his side's 1-0 win over rival Real Madrid on Saturday, but he has yet to represent the Selecao, meaning he remains eligible to play for Spain having recently acquired citizenship.
“I can’t tell you anything yet," Del Bosque told Jugones. "We're seeing if he can play for Spain, it's in process. That’s the process we’re in at the moment. The squad announcement is on Friday. We'll see.”
Should Costa be called up for Spain, his inclusion could cast doubt over the selection of Fernando Torres or David Villa, with both players yet to find their top goalscoring form so far this season.