The England forward looks set to miss at least the first 3 months of the new season as he recovers from an ankle ligament problem.
The statement reads:
West Ham United can confirm that Andy Carroll will have an operation on ligaments in his left ankle in the United States on Friday.
The England international will then have a week of recovery before starting an intensive period of rehabilitation, which is expected to take four months.
The Club would like to again make clear that this is a new injury and not in any way associated with the injury he successfully overcame at the end of last season.
Carroll said: "I'm gutted to be missing the start of the season after working hard during the summer and pre-season. Although this obviously isn't the news I would have wanted, I'm determined to come back fitter and stronger than ever before. I will be doing all I can to get back on the pitch with the lads as soon as possible."