The Reds saw their striker forced off during a Premier League victory over Tottenham, with the full extent of his ailment yet to be determined
The Brazilian forward was back in Premier League action on Saturday after returning unscathed from international duty.
He was also among the goals against Spurs, with his effort proving to be the match-winner in a 2-1 victory for Jurgen Klopp’s side.
That effort helped to preserve Liverpool’s faultless start to the 2018-19 campaign, with maximum points taken from five fixtures.
Firmino was, however, unable to see the game out at Wembley Stadium.
After tangling with Jan Vertonghen, as both men chased down a loose ball, the 26-year-old forward was left clutching his face.
He was poked in the eye by Tottenham’s full-back and was forced off with 16 minutes remaining.
Klopp told reporters afterwards when asked about the severity of the injury: “I’m not sure, but there may be an injury with Roberto, we don’t know exactly in the moment.
“It’s something with his eye, we will see.
“I didn’t see it back. I only saw the situation from around 60 yards. I have no clue what exactly happened.
Article continues below
“But it’s something with the eye and for sure in the moment it’s not comfortable for him. We will see.”
Liverpool are set to open their Champions League campaign at home to PSG on Tuesday.
Firmino will be desperate to be involved in a contest of that magnitude, but it is unlikely that any risks will be taken on his fitness this early in the season with so many challenges to come.