He came off in the 39th minute of their 4-1 win having gone down clutching his calf after slipping while playing a goal kick and, though there was no immediate verdict on how serious the problem is, Klopp did not sound optimistic.
"It's probably a bit more than a strain, we have to see, we have to make the diagnosis".
"Adrian is a good goalie", said Klopp.
Second keeper Adrian came on to replace Allison, just days after the Spaniard signed for the club.
Alisson is still set to undergo a scan and it's thought that Liverpool chiefs will wait for the results before making a decision.
Lonergan is already training with Liverpool at Melwood and can be signed despite the transfer window being closed because of his free agency.
"One of the younger ones is not allowed to play, he's only 16, and the other one had an elbow injury early in the pre-season".
That hasn't phased Van Dijk, though, who insisted that Adrián is a more than capable temporary replacement, despite admitting that Alisson's injury is a blow for Liverpool.
Kelleher will likely sit on the bench for Klopp as the Reds go in search of their first piece of silverware of the season.
Liverpool goalkeeper Adrian's Premier League experience can help him seamlessly slot into their starting lineup if first choice Alisson is out for a long spell with a calf injury, defender Virgil van Dijk has said.