Swansea City striker Michu has had ankle surgery, according to Italian club Napoli, where he is currently on a season-long loan.
A statement on the Azzurri's club website revealed Michu, 28, has had surgery to trim his right ankle at a medical institute in Spain.
"Michu is struggling a bit with his injury, he's been a bit in and out for Napoli," said Swansea boss Garry Monk.
But Monk added that the Spaniard will not return to Wales this season.
"In terms of the communications between the clubs, there's nothing about him coming back here at all."
Michu joined Swansea from Rayo Vallecano for £2.2m during the summer of 2012 and was the club's top scorer with 22 goals in his first full season.
His performances saw him linked with big-money moves, but he extended his stay in south Wales by signing a four-year deal in January 2013.
The former Oviedo and Celta de Vigo player's second season with the Swans was marred by knee and ankle problems and he scored only two goals in 15 starts in the Premier League.
In July, Michu joined Serie A club Napoli on loan, though Napoli may make the loan deal permanent.
However, his spell in Italy has been disrupted by injuries and Michu has started just two league games for Rafael Benitez's side.
But Monk says Michu's injury problems will not affect the length of the Spaniard's stay at the San Paolo stadium.
"I have to focus on the players that are here and the players that want to be here," said the Swans boss.
"Michu made his decision in the summer that he wanted to go and try a different challenge, which I supported fully.
"I've got a great relationship with Michu, I'll always be supportive with him. He's still our player.
"But in terms of this season, I'm dealing with the players that I have now."