Andy Carroll has revealed he is "absolutely devastated" that surgery on an injured ankle will see him miss the start of the season for the second year running.
The 25-year-old England international has featured just 16 times for the Hammers since becoming the club's record signing last summer and now faces more time on the sidelines with an ankle problem.
A long-standing heel injury kept Carroll out until January and he scored just twice on his return. Now he will be absent once again.
"Going under the knife tomorrow morning and absolutely devastated to be missing the start of the season!," he tweeted on Thursday evening.
The news will come as a major blow to Hammers boss Sam Allardyce as he looks to improve on the 13th placed Barclays Premier League finish in the last campaign.
Allardyce had already identified the need to add extra firepower to his squad ahead of the new season before Carroll's latest injury nightmare.
Mauro Zarate is already on board and only a work permit application is keeping Ecuador's World Cup star Enner Valencia from joining from Pachuca.
The 59-year-old may now go back into the transfer market for another forward, while questions will be asked as to whether Carroll can ever maintain a level of fitness for a prolonged period of time.
Carroll had travelled with the squad for a pre-season tour of New Zealand but the club decided they would not risk him in either game, with reports now suggesting he could be out for up to four months.
It would be a bitter pill to swallow for the former Newcastle and Liverpool man, who had spoken before his injury about the importance of keeping fit for the forthcoming campaign.
"It's a very important pre-season for me after I had a very bad season last year with injuries," he said upon landing in New Zealand. "It's important I stay fit and do everything right with the medical staff."
Without the injured Carroll in their side West Ham slipped to a 2-1 defeat to Wellington Phoenix in their first tour match - although Allardyce will be boosted by the fact Zarate scored a well-taken consolation.
The Argentina forward will now compete with Carlton Cole for a starting role in Saturday's friendly against Sydney FC, with the club hopeful that Valencia's work permit will be issued by the time they return home.
With Carroll likely to be out for some time, Allardyce may return to the transfer market for another forward to bolster his options ahead of a season-opening derby at home to Tottenham.