The ex-Swansea City man will be sidelined for a while after he undergoes surgery but is hoping to make a big impact when he returns after being plagued by the problem.
The 22-year-old Allen arrived from Swansea City last summer for 15 million pounds, but he revealed much of his debut season at Anfield has been spent battling a shoulder problem.
"It requires another operation which is always a bitter blow, but these things happen in football unfortunately and it'll keep me out for around three months when I do get the operation done," Allen told Sky Sports News.
He also stated he is unsure of a possible date for the surgery, adding: "I'm not sure to be honest, that's something that's being decided. I'll have to wait and see what comes of it.
"I'm not looking to use it as an excuse. It has been something that's deteriorated recently, and it has got to the stage unfortunately where an operation is all that can sort of resolve it.
"I'm looking forward to getting it done, get that behind me and moving on from there really."
While Allen admits playing with an injury is not ideal, he believes footballers carry a host of niggles during a campaign.
"Yeah it's not an ideal situation but like I say, there are players carrying injuries throughout a season, that's part and parcel of the game I think and you come to expect it to a degree," Allen said.