The club-record signing missed most of last season due to a troublesome foot problem and was ruled out of two friendlies on the current tour of New Zealand as a precaution.
Carroll could now be out for up to another four months after confirming he requires surgery to fix the issue.
“Going under the knife tomorrow morning and absolutely devastated to be missing the start of the season!,” he tweeted.
The news will come as a major blow to Hammers’ boss Sam Allardyce as he looks to improve on the 13th placed Premier League finish last season.
Meanwhile Ander Herrera is sure Louis van Gaal will do his utmost to keep his Manchester United players grounded after their 7-0 destruction of the Los Angeles Galaxy. United face Roma in Denver tomorrow in the International Champions Cup (kick-off 9.06pm Irish time), and Van Gaal warmed up in the best way possible on Wednesday night.
Wayne Rooney, Ashley Young and debutant Reece James all scored twice, and Danny Welbeck also found the net as United crushed the Galaxy in the Pasadena Rose Bowl.
Although he did not get on the score sheet, Herrera was United’s best player on the night. The 24-year-old, who moved to Old Trafford in a £28m transfer earlier this summer, worked tirelessly breaking up attacks and creating openings with incisive passes.
Herrera has only been working with his new manager for a week, but he knows Van Gaal enough to realise he will keep his players grounded.
“We are happy with the result but this is a friendly and we still have many things to improve on,” said Herrera.
“Our coach is very demanding, he always looks for perfection and he won’t let us sit back and relax or sit back, we still have a lot to prove.”