The Reds could be without the 32-year-old for a trip to Southampton on Saturday, which leaves Jurgen Klopp short on options between the sticks.
Jurgen Klopp has hinted that Adrian could be a doubt for Liverpool's clash with Southampton on Saturday after suffering an injury at the hands of a supporter following the UEFA Super Cup final.
The Reds lifted the continental trophy after a penalty shootout victory over Premier League rivals Chelsea on Wednesday night in Istanbul.
The match finished 2-2 after extra-time, but Liverpool picked up their second piece of silverware this year after Adrian saved Tammy Abraham's decisive spot-kick.
The Spanish 'keeper started the match in the absence of number one Alisson, who suffered a calf injury in a Premier League curtain-raiser against Norwich last Friday.
Klopp is now sweating on the fitness of Adrian too, who picked up a knock after being kicked by a fan during Liverpool's Super Cup celebrations.
The German boss told a press conference on Friday: "I don't understand why in the world of social media when we are all together, a supporter jumped over something and kicked [Adrian's] ankle. It is swollen but we have to see.
"There's no doubt about how much we love our fans, but if they can all stop doing that, please. It's not funny. I like the fact that there are not fences in the stadiums but there has to be some responsibility from the fans as well.
"Norwich, Istanbul, people ran on the pitch. It's not funny. The girl in the Champions League final made money obviously, but there's a lot of responsibility for fans.
"Apart from that, it was a brilliant night for him."
Adrian made his Liverpool debut during the 4-1 win over Norwich after Alisson was forced to make way in the first half.
It is not yet known when the Brazil international will return to action, though it is set to be a number of weeks, and if their summer signing is also unavailable, reserves Andy Lonergan and Caoimhin Kelleher will have to be called into Klopp's squad.
Veteran Lonergan trained with the club during pre-season and was offered a short-term deal in the wake of Alisson's injury despite playing the majority of his career in the lower leagues.
Kelleher, meanwhile, is an academy product who is yet to play a senior match, though he has represented Republic of Ireland at youth level.
The Liverpool boss added: "We need to think about Saturday to find a way to win the game.
“Andy Lonergan is in training with Kelleher and we have them if we have to make a decision.
“Adrian was a week before, Lonergan has trained with us. Kelleher has potential but is not 100 per cent yet. We will see.”
The Reds will be expected to pick up another three points against Southampton at St Mary's this weekend, as they aim to go one better than last season and beat Manchester City to the title.
After the clash with the Saints, Liverpool will turn their attention to a huge home fixture against Arsenal on August 24, who won their opening game of the campaign 1-0 at Newcastle.