Alisson, 26, has missed nine games in all competitions after suffering a calf injury in the premier league opener against Norwich on 9 August.
After the game against Leicester and the international break, they face United at old trafford on 20 October.
“There are two opinions,” said Klopp. “One is Alisson’s and the other is the medical department, which is more cautious. We have to wait and see.
“In training, he looks really well but it was a serious injury and we don’t want to take any risks.
“We have to see for Leicester and the manchester united game – probably 100% but we will see.”