Matt Ritchie is facing two months on the sidelines after suffering a shoulder injury in Newcastle's draw at Tottenham on Sunday.
The 31-year-old sustained the injury during the second half of the game in north London when contesting an aerial challenge with Spurs' Matt Doherty.
Ahead of the Carabao Cup tie at Newport on Wednesday - live on Sky Sports - Steve Bruce said: "He will probably have an operation today [Tuesday] - I know he's seeing the surgeon today - or certainly in the next 24, 48 hours.
"It's a very similar injury to Fabian Schar, disruption of the joint, so how unfortunate are we? To have one is bad enough, but to have two in a matter of weeks is incredible.
"It looks as if he'll need an operation and it will be performed very shortly."
Bruce says he will not look to sign a replacement for Ritchie before the transfer window closes on Monday.
Summer transfer window - key dates and times
The summer transfer window closes at 11pm on Monday October 5 with a feast of activity lined up on Transfer Deadline Day on Sky Sports News and across our Sky Sports platforms.
A domestic-only window for deals between the Premier League and EFL then runs from October 5 and closes on Friday October 16 at 5pm. Follow all the news and analysis on SSN and across Sky Sports' digital platforms, including with our dedicated Transfer Centre blog.