Massadio Haidara has suffered a setback in his return from injury.
Newcastle United manager Rafa Benitez had hoped to have Haidara available for the April 2 game against relegation rivals Norwich City.
But the full-back, sidelined since October with a knee problem, twisted his knee in training today, and he is now being assessed by the club's medical team.
“We don’t know yet (how long he’ll be out for) but he twisted his knee," said Benitez.
"I think he’ll have a problem. Now we have to manage the problem that we have.
“Colback can’t play (at Norwich), but we will see what the doctor says about Haidara. If we have problems, you have to find solutions.
“We have an international break too, you have to wait and after when they come back start thinking about the team.”
And Jack Colback – who has deputised for Dummett and Haidara at left-back – through suspension, having picked up a two-game ban for his 10th booking of the season in last Tyne-Wear derby.
Benitez will have to decide who should play out of position at left-back at Carrow Road when his international players return late next week.