Middlesbrough defender Emanuel Pogatetz will miss the start of the season due to a knee injury.
Pogatetz suffered the injury during the club's pre-season trip to Austria and it was originally thought it would only be a minor problem.
After a scan on Pogatetz's knee, Boro boss Gareth Southgate stressed the need to make a quick decision on whether surgery would be required.
The Premier League club have now opted to book the Austrian in for a cartilage operation on Thursday.
"It's a blow, but we are hoping to have him back as soon as possible," Southgate told the club's official website.
Southgate is now short on experienced centre-halves for his side's opening game of the season against Blackburn Rovers on 11th August.
Jonathan Woodgate and Robert Huth are both likely to miss the match, while Chris Riggott is aiming to shake off a foot injury to be available.