Martin Dubravka is a doubt and with No 1 keeper Nick Pope crocked, the German could play his first Champions League game since the 2018 final when his howlers handed Real Madrid a 3-1 victory over the Reds.
Those two infamous errors, way back 2,028 days ago, came at 0-00 after Karius was clattered by the elbow of Sergio Ramos early in the second half.
He soon rolled the ball for Karim Benzema to nip in and put Real in front, then let a long-range strike slip in for the second of Gareth Bale’s two goals.
Karius, now 30, did not play again for Liverpool and has featured just once for the Magpies – in last season’s Carabao Cup final defeat to Manchester United – since arriving as a free agent last September.
Dubravka was not seen at training yesterday.
Asked if he is fit for tomorrow night’s clash, Howe said: “That is slightly unclear.
“It’s not really a position I want to rotate.
“Every team benefits from a settled back four and goalkeeper but let’s see what happens.”
And Toon striker Callum Wilson backed Karius to shine if called upon at St James’ Park on Wednesday night.
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A win could see Newcastle qualify for the Champions League knockouts if Borussia Dortmund avoid defeat against PSG, while a draw would ensure the Europa League.
Wilson said: “All of our goalkeepers really, even Mark Gillespie, people you don’t see as much of, they’re all top goalkeepers.
“They will give you a run for your money in training during finishing practice.
“Whoever is between the sticks, I’m sure they’ll be more than capable.”