Michu has not returned to pre-season training with Swansea City as the forward and the club continue to assess his next move
The Spaniard, 29, spent last season on loan at Italian side Napoli, but suffered with injuries and only played five games for Rafa Benitez's team.
Michu was a £2m signing from Rayo Vallecano in July 2012 and scored 22 goals in 43 games in his first season.
But he only scored six goals in his second season with the Welsh side.
Michu won his only international cap for Spain in 2013, in a 2-1 win against Belarus.
Napoli have an option to buy Michu but after his injury problems the Italian club is unlikely to buy the player.
In May, Swansea chairman Huw Jenkins admitted that Michu may not play for the Premier League club again.