The former Newcastle United forward is on a season-long loan from Anfield and after scoring four goals in his past five outings, Hammers boss Sam Allardyce is keen to have him as a permanent fixture at Upton Park.
But he understands that FIFA's Financial Fair Play rule may squander West Ham's attempts to bring in the 24-year old who cost Liverpool £35million in January 2011.
"The hardest thing is the overall package, the overall negotiation which needs to go on to make sure it can be sustainable in terms of what we can do," said Allardyce.
"I will still point towards financial restrictions being implemented next season - they could blow the whole deal in one go.
"Financially you are restricted to be able to do it.
"Somebody will have a bigger budget than us somewhere, but I tell you that is what's going to happen, I might not be able to afford Andy Carroll, full stop, even if I wanted him, even if the chairmen wanted him, even if we all wanted him, which we do, it will not be allowed to happen."