Andy Robertson suffered an injury during Liverpool’s friendly against Athletic Bilbao on Sunday and is a doubt for their Premier League opener against Norwich City.
The Scotland full-back, 27, was helped off the pitch by medical staff after he fell awkwardly when attempting to block a cross.
Robertson looks to have suffered an ankle injury and will undergo further assessment on Monday.
He could miss the clash against Daniel Farke’s men on Saturday, with an announcement expected in the next few days.
When asked about Robertson after the 1-1 draw, manager Jurgen Klopp said: “We don’t know how serious it is. It was pretty painful and that is why Andy went off.
“He got the ball on the front of his foot, twisted his ankle. The pain settled already but we cannot say without further assessment.
“He needs to get a scan and then we will know more.”
After the match, the player tweeted: “Your support today was amazing! Thank you for all your messages, I’m positive but let’s see what tomorrow brings!”
— Andy Robertson (@andrewrobertso5) August 8, 2021
Liverpool took the lead in the 13th minute thanks to Portuguese forward Diogo Jota.
However, Alex Berenguer brought the Spanish side level shortly before half time.
Having Robertson on the sidelines would be a major blow for Klopp and Liverpool.
He started every Premier League match last season, while only seven outfield players managed more minutes.
His likely replacement, Greek left-back Kostas Tsimikas, played just seven times in all competitions.
Only one of those appearances involved a full 90 minutes, too.
On a more positive note for the club, influential centre-half Virgil Van Dijk continued his road to recovery with 71 minutes.
That marks his longest game since a cruciate knee ligament injury in the Merseyside derby ended his campaign.
Van Dijk pulled off some great cross-field passes throughout the match and could have scored a number of headers.
He was partnered at the back by Joel Matip, who also spent a large amount of the 2020/21 season injured.
The team Klopp selected could be close to his starting eleven against Norwich next weekend, Robertson notwithstanding.
Alisson started in goal, a back four was made up of TAA, Van Dijk, Matip and Robertson, the midfield included James Milner, Naby Keita and Harvey Elliott, with Mo Salah, Jota and Sadio Mane up front.