Injuries have meant a stop-start season on loan in east London for Carroll, who is ineligible for Sunday's trip to Liverpool under the terms of his deal.
That means another 90 minutes on the sidelines a week after the 24-year-old - a summer transfer target for the Hammers - showed a glimpse of his best form with two goals against West Brom.
Allardyce said: "Andy looks to be in full flow and good goalscoring touch, which is what we've been waiting for a long time.
"It's frustrating to be without Andy for Sunday and it is for him as well but that's the way the fixtures have fallen."
Allardyce has never made a secret of his wish to make Carroll's loan permanent - as long as the terms suit West Ham.
He said "I think there'd be a lot to be discussed between ourselves, Liverpool and Andy before that could be the case, but once we're secure then we'll move on with that business as quick as we possibly can.
"I wouldn't have spent as much time as I did trying to get him here if I didn't want him here on a permanent basis.
"We would have hoped he'd score a few more goals, but the circumstances around why he hasn't are ones we can put right. In other words, keeping him match-fit would mean more goals."
West Ham have not won at Liverpool for almost 50 years, but Allardyce said: "On any given day on your best form you can win anywhere.
"For most of those 50 years Liverpool have been so much better than everyone else that you wouldn't expect to win there, but we're capable of winning there and if we're on top form and take our chances we can."