The 23-year-old Denmark centre-half has been out of action since September after breaking his metatarsal, leaving manager Rafael Benitez perilously short of cover at the heart of his defence.
"He is very close to starting a game for the first team.
"The injury he had wasn't a bad one but we had problems also with Xabi Alonso, so we needed to be careful and we have missed him.
"We will be much better in the second part of this season."
"He could be available for Saturday," he said. "He is improving a lot with the physios so he could be an option for the next game."
The Spaniard also confirmed that full-backs Alvaro Arbeloa (calf) and Fabio Aurelio (hamstring) are making good progress, with the former a possibility for the clash at the Riverside.