Borussia Dortmund have confirmed that left back Raphael Guerreiro has pulled out of the Portugal squad to face Italy in their opening UEFA Nations League match due to a thigh injury.
The full back - who can also feature on the left wing - sat out Portugal's 1-1 friendly draw with Croatia on Thursday due to unconfirmed fitness issues, but the announcement from Dortmund on Twitter clears up the situation.
The announcement translates to: "Raphael Guerreiro has prematurely left the Portugal squad due to a muscle injury in his thigh."
Remarkably, it comes as his fourth muscular injury of 2018, missing 17 games to injury in total since the turn of the year.
Previous muscle-related knocks have kept him out of action for anywhere from three to five weeks, but the timeline on this particular injury hasn't yet been confirmed.
It will come as a blow to Guerreiro, who played each of Portugal's four matches at the World Cup, but has been used only as a substitute so far in the Bundesliga, with Marcel Schmelzer the preferred choice at left back - perhaps partly due to the recurring nature of Guerreiro's muscular issues.
Dortmund have enjoyed a solid start to the league season, winning 4-1 at home to Leipzig before a 0-0 draw with Hannover, but are likely to have to cope without their current second choice left back for upcoming fixtures with Eintracht Frankfurt in the Bundesliga, and Club Brugge in the Champions League.
Portugal, meanwhile, will have no short notice opportunity to call up a replacement to Guerreiro, so it's likely that Rui Mario - who played there against Croatia - will fill in against Italy on Monday.