The Republic of Ireland international, 29, a consistent figure since joining the club in the summer of 2022 from second-tier rivals Blackburn Rovers, has been sidelined since the club's first league win of the season against Southampton in September.

Despite Lenihan rehabilitating for a spell in a bid to clear up the problem, the injury issue has not improved and he has now revealed on Instagram that he has undergone surgery and will not play again this season.

He wrote: "Road to recovery begins today after undergoing a successful operation.

Middlesbrough vice-captain Darragh Lenihan, who has been ruled out for the rest of the season following surgery. Picture: Stu Forster/Getty Images.

"Gutted to be missing the rest of the season, but I’ll be helping the lads as best I can from afar."

Lenihan is the second senior Boro defender to be ruled out for the rest of the campaign, with Tommy Smith also out with a serious ankle injury sustained in the win against Birmingham City last month.

Major summer loan signing Lewis O'Brien is also currently out of action with an ankle issue.

The development regarding Lenihan leaves the club light in terms of their central defensive options.

The Teessiders, pushing for a play-off place alongside East coast rivals Hull City, return to action following the international break at Bristol City this weekend.

After hosting Preston North End to end November next Tuesday, they make the visit to Elland Road to face Leeds United on December 2.

Championship play-off chasers Middlesbrough FC suffer major injury blow with Republic of Ireland defender sidelined for rest of 2023-24 season