Spain travels to Equatorial Guinea for a game on Saturday before playing South Africa next week.
Costa had been embroiled in a trans-Atlantic, national team tug-of-war between World Cup champion Spain and host Brazil before choosing to play for the defending champions in the buildup to next year's tournament.
While Costa did feature in a friendly for Brazil, he never played a competitive match for his native country so he remains eligible to play for the European and world champions. Costa has been playing in Spain since 2007 and credits his success to his adopted home.
Costa's next chance to impress coach Vicente del Bosque would be in March when Spain plays Italy in a friendly.
Costa has been one of the revelations of the season, scoring 16 goals as Atletico sits second in the Spanish standings and has already qualified for the next round of the Champions League.