The Brazilian played all 38 league games last season as the Reds narrowly missed out on the title.
A 4-1 victory over the Canaries at Anfield saw Liverpool temporarily take hold of top-spot in the English top-flight table.
However, an otherwise positive start to the new campaign for Jurgen Klopp's men was soured somewhat by a blow on the injury-front.
A team with better quality attacking players would have punished a Liverpool defence that doesn't seem to have found the right balance in recent weeks, with the concern over the goalkeeper now the most pressing issue for Klopp.
Klopp has offered similar reassurance although, such is Liverpool's goalkeeper shortage, the manager said Adrian needs to be "wrapped in cotton wool" rather than overexerted in training sessions.
Liverpool were already 3-0 up when Adrian was called upon to replace Alisson, who managed to leave the field without a stretcher despite looking in a great deal of pain.
The Spaniard is expected to retain his position between the Reds' sticks until Alisson returns to training next month, with our televised trip to Anfield on September 14 a fixture he may be able to return for.
In the absence of further depth in the case that Adrian also picks up a problem, though, the Merseysiders are set to dip further into the free agent pool imminently.
Lonergan, most-recently of Rochdale (on loan from Middlesbrough), trained with Liverpool throughout the summer, amid a goalkeeping crisis.
"I'm not anxious at all about how he will do it in the long term, but in the short term the problem is just that he came here with no club when we signed him", Klopp said.
"I don't want to make now [an] exact prognosis on when he will be back but it will not be Wednesday for sure, so now then we have to see". He's a brilliant character, a really nice lad and helped us a lot in the pre-season and now we chose to work together with him'. It takes a while, it takes a couple weeks for sure, and we have to see. "We don't have to talk too much about it, that's what the experience is for", Klopp told Liverpool's official site.