The Liverpool No.1 sustained the issue in the first half of the 4-1 win over Norwich City on August 9 and was subsequently ruled out for ‘the next few weeks’ by Jürgen Klopp.
Summer signing Adrian has stepped in for Alisson and enjoyed a fairy tale start to his Reds career with the decisive save in the UEFA Super Cup success against Chelsea.
Alisson continues to work on his rehabilitation at Melwood and Achterberg anticipates a clearer idea of his potential return date after the forthcoming international break.
“Ali is good. He’s in every day for treatment and they try to improve things,” the first-team goalkeeping coach told The Athletic.