Liverpool goalkeeper Alisson will miss next week's UEFA Super Cup match against Chelsea after suffering a right calf injury in Friday's Premier League season opening win over Norwich City.
The Brazil international came off in the 39th minute of the match after slipping and holding his calf. He waived off the stretcher but needed assistance from the team's trainers to come off the pitch at Anfield.
Liverpool had four first-half goals to ensure a 4-1 win over newly promoted Norwich.
"We have to see how serious it is and deal with it," Liverpool manager Jurgen Klopp said of Alisson's injury in a post-match news conference. "It's a calf injury. He couldn't carry on, which is never a good sign... he will not play [in Wednesday's Super Cup]."
Alisson -- who started all of last season's 38 Premier League matches -- was instrumental in Liverpool's Champions League title run in May, as well as Brazil's Copa America victory this summer.
Liverpool next travel to Istanbul where they will play defending Europa League winners Chelsea for the Super Cup.
Newly signed Spanish goalkeeper Adrian came on for the Reds, his first game in uniform since joining from West Ham on a free transfer this week. His only blemish in his Anfield debut came when Teemu Pukki, who led the Championship last season with 29 goals, scored for the visitors just past the hour mark.
"[Adrian] is a very confident guy and he came in and I don't think he wanted to sit only on the bench for the next couple of years," Klopp said. "He made himself ready.
"He is 32, a calm guy, emotional as well, good with his feet - how we saw - and that's really important for us."
Liverpool sold longtime keeper Simon Mignolet last week to Belgian side Club Brugge. Caoimhin Kelleher as is expected to serve as Adrian's understudy for the Super Cup fixture, with the youngster having recently returned to training following a broken wrist.
"There are a lot of good things, but you still don't want to have a situation where one goalie is fit," Klopp said. "That's how it is, but we have to see."
ESPN FC's Melissa Reddy contributed to this report.