Newcastle United boss Alan Pardew has hinted that he could recruit a goalkeeper on emergency loan following the injury to Jak Alnwick.
That leaves 17-year-old Freddie Woodman in line to face Sunderland in Sunday's Tyne-Wear derby.
"He has an injury to his shoulder so we're going to have to see," he told Sky Sports News.
"It is something we might have to look at tomorrow because there is no way that a 17-year-old (Woodman) - that's our fourth-choice - should be allowed to go in goal at this level.
"We will perhaps talk to the Premier League tomorrow about Jak's situation."
Krul is expected to be out until mid-January with an ankle injury, while a thigh problem has sidelined Elliot.