Villa sustained an ankle injury in Atletico Madrid's win over Celta Vigo on Sunday afternoon and was forced to pull out of the party to face Belarus and Georgia in a World Cup qualifying double-header.
His misfortune gives Michu the chance to represent his country for the first time at any level.
The 27-year-old has been a revelation at Swansea since moving to the Premier League from Rayo Vallecano in the summer of 2012.
He scored 22 goals in his first season in south Wales and already has five to his name in 2013/14.
The European and world champions take on Belarus in Palma on Friday night before hosting Georgia in Albacete four days later.