Newcastle's £60million record signing Alexander Isak has been forced to leave the Sweden national-team camp because of injury.
The striker celebrated his 23rd birthday on Wednesday but trained alone from his international team-mates.
While Isak's problem was initially not thought to be serious, Sweden boss Janne Andersson revealed on Thursday he would miss their Nations League games against Serbia and Slovenia.
He said: 'It is of course sad mainly for Alex but also for us as a team. After speaking with both our medical team and Alex, it is the right decision for him to leave.'
The exact nature of the injury is not yet known, but Isak said: 'It feels very sad to have to leave the team. I had longed to play in the blue and yellow shirt again. I wish the boys the best of luck on Saturday and Tuesday.'
Newcastle will now await the return of Isak to Tyneside before trying to determine the extent of the injury. The good news for Eddie Howe is that Callum Wilson will return from a hamstring layoff at Fulham a week on Saturday.
However, there will be concern that Isak could miss games so soon after arriving from Real Sociedad. He has scored two from three matches so far, although Howe believes there is a lot more to come once his team-mates learn how to play to his strengths.
Speaking after Newcastle's 1-1 draw with Bournemouth on Saturday, Howe said: 'He's learning, and not just how the team plays, but also how his team-mates around him play.
'Again, there were flashes from him, but I don't think, as a team, we did well enough to get him into goal scoring positions. We didn't feed him the ball early enough. He was a little bit isolated.
'But let's look at the positives – he took his penalty brilliantly and he worked hard for the team. He definitely contributed, but we know we can get him involved a lot more than that.'
