The centre-half has been sidelined with a knee injury since November 11 and is now back in training although Benitez says it is too difficult to suggest when he will be back on the pitch.
"The knee is quite complicated," he said.
"At least he's now on the pitch - that is positive news - but we cannot say, we cannot predict how long it will take."
"I hope so but I am not a doctor," he added about the chance of Terry playing before the end of the year.
"So I cannot guarantee anything."