Carroll was ruled out until November earlier this week after suffering an ankle injury, and the England striker was set to undergo surgery on Friday morning.
The blow comes after the former Liverpool and Newcastle forward spent a large portion of last season on the sidelines with a recurring heel problem.
Carroll featured just 15 times for the Hammers last term, costing the Londoners around £1 million per game, and after his latest set back, owner Sullivan, suggested the club were given the wrong information from the medical team prior to his permanent move from Liverpool in 2013.
Sullivan is quoted as saying by talkSPORT: "Had we known what we know now we wouldn't have signed the player. But it's easy to be wise after the event. It was desperate last year... We probably made a mistake by putting all our eggs in one basket.
"We were assured by our physio - who has since left the club - that the player would be available for the start of the season.
"He wasn't available until January or February. A mistake was made and we were given the wrong information. We based our decision and our purchase of the player on what the medical department told us.
"We have to bring in another striker and we’re working on it now to buy one, or loan one, or both. You can never have enough strikers and really with Andy gone we haven’t got enough."
It has been a miserable 12 months for Carroll on the field.
The tall target man scored just twice after eventually making his Hammers bow in January, months after signing from Liverpool, and the striker missed out on a place in the England World Cup squad.
Carroll has made just 41 appearances since initially moving to the Hammers on loan in the summer of 2012.