Quoted in the Northern Echo, Poyet said:
"From the beginning of the morning, we started to deal with the Lee Cattermole situation. I am late because in the last few hours we have got to a really impressive point. The offer and the situation is not easy. Nothing is finalised. It is still ongoing."
Cattermole would be a significant departure for Sunderland, having first joined the club from Wigan Athletic back in 2009. He's made 14 Premier League appearances this season and has been a significant part of Poyet's side, though Stoke's bid is seemingly big enough for the Black Cats to loosen their grip on the tough-tackler.
The 25-year-old didn't train for Sunderland today, though having sat out the last match with a knock, that may be meaningless.