West Ham's Andy Carroll could be out of action for four months after tearing ligaments in his ankle.
The former Liverpool player, 25, will have an operation on Friday in the United States.
Carroll picked up the problem on the Hammers' tour of New Zealand, reporting a sore left ankle in training.
He tweeted: "Going under the knife tomorrow morning and absolutely devastated to be missing the start of the season."
|Andy Carroll's injury record at West Ham|
|September 2012 - Picks up hamstring injury in his first game on loan - out for a month|
|November 2012 -Twists knee against Manchester United - sidelined for two months|
|May 2013 -Damages heel in the last game of the season - out for seven months|
|July 2014 -Tears ankle ligaments in pre-season - expected to be out for four months|
The club only discovered the full extent of the injury on Thursday evening and say Carroll will have a week of recovery after his operation, before undergoing an "intensive period of rehabilitation".
"Although this obviously isn't the news I would have wanted, I'm determined to come back fitter and stronger than ever before," said the former Newcastle striker. "I will be doing all I can to get back on the pitch with the lads as soon as possible."
Carroll missed West Ham's 2-1 defeat at the hands of Wellington Phoenix and has been plagued by injury since moving to Upton Park for a club record £15m from Liverpool after impressing during a loan spell.
The player missed the majority of 2013-14 with a heel problem - managing just 15 league appearances - and also failed to force his way into England's World Cup squad.
|Andy Carroll's Premier League record|