Poyet had been looking at bringing in a new midfielder and a striker on Monday but a promising diagnosis on Cattermole's knee and groin injuries inspired the Uruguayan to shelve any potential transfers.
Cattermole has not played this year and could miss the rest of February but Poyet is confident he will get enough out of his 26-year-old captain that he did not get involved on deadline day.
"I would say it's two or three weeks for Lee," Poyet told the Northern Echo.
"It is decent news. I was a little bit nervous. It was important we had clarification before the transfer window finished.
"If it had been bad news and a long-term injury maybe we would have had to move quickly. He'll rest for four or five days and then slowly start training.
"The specialist is positive he will be back without any problems."
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