Holland international Jonathan de Guzman has been ruled out of Swansea's opening Barclays Premier League match against Manchester United on Saturday because of concussion.
As well as missing the curtain raiser against the defending champions, midfielder De Guzman will also sit out Wednesday night's friendly with Portugal after suffering concussion during a training session with the national team.
The 25-year-old collided with team-mate Dirk Kuyt during a session in Faro on Tuesday.
Both players remained motionless after the clash which sent panic through the Holland camp, before De Guzman quickly regained consciousness and Kuyt required five stitches to a facial wound.
The injury means the Villarreal loanee could be sidelined for seven to 10 days, so he could also miss next week's Europa League play-off first leg against Romanian side Petrolul Ploiesti.