Michu has left Swansea City after agreeing a financial settlement with the club for his departure.
The 29-year-old Spain forward was the club's top scorer in 2012-13 with 22 goals in a spectacular first season after a £2m move from Rayo Vallecano.
But he has not played for them since April 2014, and spent last season on loan at Napoli, where injuries meant he only played six times.
His Swans contract, which he extended in January 2013, ran until next summer.
He has not featured in Swansea's squad since returning from Napoli, with chairman Huw Jenkins saying in May the player was unlikely to play for the club again.
He is expected to return to Spain, having been training with fourth-tier side Langreo.
Michu won a Spain cap and was linked to Arsenal after his surprise first season in British football.