Newcastle midfielder Jack Colback has been ruled out for up to six weeks with a knee injury.
The former Sunderland player sustained the injury following a challenge by Lee Cattermole in the early stages of the second half of Sunday's 3-0 Barclays Premier League loss to their fierce rivals.
The Tyneside club tweeted: "Newcastle United midfielder Jack Colback will be sidelined for up to six weeks with a knee injury, following further scans and assessment on Thursday. The injury is not as bad as first feared."
The 26-year-old has started nine of the Magpies' 10 top-flight games this season.
