Anthony Elanga was stretchered off after suffer a nasty challenge in Newcastle’s 2-1 pre-season win over Valencia on Saturday.
The Swedish winger was chopped down by veteran Valencia defender Jose Gaya, who was subsequently shown a red card.
Newly-appointed Magpies boss Matthias Jaissle admitted he felt “fear” watching an agonised Elanga be carried off the field - but despite the concerning optics, he thinks the 24-year-old has escaped serious injury.
"It seems to be not bad, so we are pleased,” he said. “I hope it's true, then he can start again next week.
“I was in fear, definitely, but now I'm more relaxed as the medical department is showing almost green lights, and there's nothing serious."
Jaissle endured an early setback in his maiden outing as Newcastle manager when Filip Ugrinic fired Valencia ahead inside four minutes, but his side fought back at the Estadio Mestalla with substitute Yoane Wissa scoring twice in the second half.
Goalkeeper Lukas Hornicek, midfielder Aladji Bamba and winger Bazoumana Toure made their debuts, while 18-year-old Sean Steur impressed off the bench, with Jaissle turning to his youth on a day that saw former captain Bruno Guimaraes complete his move to Arsenal.
While an impressive comeback from his side, Jaissle is not getting ahead of himself and asserts there is still a lot of work for his side to do ahead of their Premier League opener against Liverpool in two weeks.
"It was a friendly today,” Jaissle said. “We will not smash the locker room now and celebrate a lot.
"We're quite balanced. We know what it is about. Now it's pre-season, and we're still looking to work on it. It's just a journey."
He added: "Time is the key. They're young lads. It's never going to be easy in football, especially at the highest level, but we're here to help them."
