The midfielder's current deal expires at the end of the season and he declined to extend it in the summer when Paolo Di Canio was in charge.
Yet Colback, 24, is happier under new Black Cats boss Gus Poyet and is keen to re-sign.
He told The Sun: "We've been in talks for a while now - it just takes time.
"With the position the team is in there haven't been a lot of discussions, but that's natural. When we start winning that might pick up a bit.
"My last contract took quite a while."
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