Liverpool have been rocked by the news Roberto Firmino has suffered a “serious hamstring injury”, with it yet to be determined when the Brazilian striker will be ready to return to action.

The 30-year-old frontman lasted just 33 minutes of the Champions League clash with Atletico Madrid after being introduced as a half-time substitute.

He faces another enforced spell on the sidelines, although Jurgen Klopp is hoping another international break could arrive at a good time for the Reds.

Klopp told Liverpool’s official website: “Bobby is not good news with a serious hamstring injury, really unfortunate. We don’t know exactly how long he will be out but it will be after the international break. We have to work on that.”

Joe Gomez will miss Sunday’s trip to West Ham with a calf complaint, while Curtis Jones has suffered eye damage.

Klopp said on the 20-year-old midfielder: “Curtis is a completely different story [to Firmino], he was very unlucky in training – he got a finger that scratched the eye.

“I had a lot of injuries to players in my career, that was not involved. He is on the way back but we have to see how long exactly.

He will be back after the international break, for sure, but in the international break we have to see when he can start doing proper stuff again. Joey hopefully after the international break as well.”

Liverpool head to London Stadium this weekend second in the Premier League table, unbeaten after 10 games but three points adrift of leaders Chelsea.