Colback left the field early in the derby defeat to Sunderland with a leg injury.
Newcastle United fear that Jack Colback could be sidelined for a number of weeks during a key stage of their season after being on the wrong end of a tackle from Lee Cattermole in the Tyne-Wear derby defeat to Sunderland at the weekend, the Shields Gazette reports.
Colback had to leave the field before the end of Newcastle's 3-0 defeat at the Stadium of Light because he suffered an injury to his leg.
The midfielder has already been ruled out of the weekend's home game against Stoke City as he serves a one-match ban for picking up his fifth yellow card of the season.
November looks as if it could be a key month for Steve McClaren's side with a visit to Bournemouth that could potentially prove pivotal at this stage of the season, with the Cherries also finding life in the league pretty difficult.
As it stands, Newcastle sit 19th in the Premier League table, two points adrift of safety, and also have two sides in pretty good form in November, in Leicester City and Crystal Palace. This is before they face games against Liverpool and Tottenham Hotspur.
Without Colback going into these kind of games would be a huge blow to the side as a pretty vulnerable back line will need all the protection it can get as the side will try and get their season on track.
With just the one win this season, and a derby defeat with controversial decisions at a key moments in the game, the last thing they need is a key absentee to go with other high profile members of the side at this stage of the season.