Newcastle captain Jamaal Lascelles is expected to be out for "six to nine months" after scans revealed he needs surgery on a knee injury.
Lascelles ruptured the anterior cruciate ligament in his right knee during Saturday's win over West Ham.
The 30-year-old will have surgery next week.
Fellow centre-back Sven Botman suffered a similar injury against Manchester City earlier this month and has also been ruled out for up to nine months.
Lascelles was forced off after 17 minutes of Saturday's 4-3 win at St James' Park.
In a statement, the club said: "After seeing a specialist consultant, he is expected to undergo surgery next week and will be out for six to nine months.