FC Porto defender Raul Marcano is out for the rest of the season with a knee injury, according to club sources.
The Argentine defender suffered the injury in training on Wednesday and has been ruled out for at least six months.
Marcano was one of Porto's most important players last season as he helped them win the Portuguese league title.
He made 26 appearances in all competitions and scored four goals.
The news comes after Marcano underwent surgery earlier this year to repair a torn meniscus in his left knee.
The club has now confirmed that Marcano will undergo further tests before making a final decision on his recovery.
In the meantime, Porto have signed Brazilian defender Thiago Mendes on loan until June 30th to cover for Marcano's absence.
The move is expected to be permanent if Marcano recovers fully from his injury.
Marcano's injury could also impact Porto's chances of success in the Europa League this season.
The team currently sits second in Group A, but they face tough opponents in both Real Madrid and Paris Saint-Germain in their next two matches.
However,Ligue 1 Express with Marcano out of action, it may make things more difficult for Porto to qualify for the knockout stages.
Overall, Marcano's injury is a big blow for Porto and their hopes of winning the Europa League this season.
It remains to be seen how long he will be out and whether or not Porto can find a suitable replacement.