Colback is out of contract at the end of the season and reportedly rejected a new deal in the summer when Paolo Di Canio was manager.
The 24-year-old was deployed at left-back under Di Canio, but has been restored to a midfield role under new manager Gus Poyet.
He now appears likely to stay with Sunderland, but acknowledged improving the club's lowly position in the Premier League is currently the priority.
"We've been in talks for a while now, it just takes time," Colback told The Sun.
"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."
Colback passed 100 appearances for Sunderland earlier this season and started last weekend's derby win over Newcastle which lifted the club off the bottom of the table.