Newcastle new boy Yoane Wissa is to see a specialist over the knee injury he suffered in Congo DR's World Cup qualifier defeat by Senegal.
Head coach Eddie Howe has revealed the 29-year-old, a £55 million ($74.4m) summer signing from Brentford, will miss Saturday's Premier League clash with Wolves in which he was expected to make his debut.
He faces a race against time to be fit for Thursday night's Champions League opener against Barcelona.
Asked if Wissa was fit and available for the weekend, Howe said: "Unfortunately not, no, so he won't make this game.
"I saw him for the first time yesterday, he's feeling the effects of the injury he sustained just before he came off, so we're going to have to see how he is."
When probed further as to how long Wissa could be sidelined, Howe added: "I don't know currently as I sit here. I think he'll go away for tests and maybe see a specialist to see."
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Newcastle have been dealt a further blow by the news that fellow summer signing Jacob Ramsey will be missing until after the next international break with an ankle problem.
Howe said: "I think he'll miss the game having suffered from that tackle against Leeds. His ankle swelled up at halftime and he had to come off and, unfortunately, I think he'll be missing until the next international break, so that's a big blow."