West Ham United co-owner David Sullivan admits they need to find a new striker after losing Andy Carroll to injury.
The England international faces four months out, with ankle surgery now confirmed for the Geordie.
Sullivan told talkSPORT: "It was desperate last year... We probably made a mistake by putting all our eggs in one basket.
"Had we known what we know now we wouldn't have signed the player. But it's easy to be wise after the event. 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."
He added: "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."
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