Newcastle boss Eddie Howe admits Nick Pope's injury is a heavy blow.
The goalkeeper suffered a shoulder dislocation during their 1-0 win against Manchester United.
Howe said: "It will be a massive blow for us if he is ruled out for any length of time. It looked really innocuous, but that is usually the way and they are normally the more serious ones.
"You could see he was in distress and it looked like he dislocated his shoulder just diving.
"Martin Dubravka came on in a tricky situation with 10 minutes to go, narrow lead. which is not nice for a goalkeeper, so I have to compliment him for doing so well."