Current loan club Nottingham Forest are understood to have an option on making the loan permanent but Colback admits it may not be as straightforward as the deal going through at the end of the year.
“I have a year left on my contract at Newcastle. When I saw the reports that said I was out of contract, I had to check with my agent that I did have a year left," he told Nottingham Live.
“It is not as though I am looking at it and thinking that I will go back to Newcastle and try to get back in the team. I am realistic enough to know that, if the current manager is still there, I am not going to be playing.
“I am not sat here thinking that things might change if he goes – the way I am looking at it is to think that I haven't played for the club for two years and it is unlikely that I will do again.
“We will see what happens in the summer.
“I really enjoyed my time at Newcastle. Getting relegated was hard , because it is my home town club and I have a lot of family and friends up there. That was tough to take.
“In the time I was there, I played a lot of games. It did not end too well. But that happens with football. It is one of those things that is out of the blue."